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Measurement Data (measurement + data)
Selected AbstractsThe influence of grout and bentonite slurry on the process of TBM tunnelling.GEOMECHANICS AND TUNNELLING, Issue 3 2009Der Einfluss von Ringspaltmörtel und Bentonitsuspension auf den TBM-Vortrieb Abstract The bentonite and grout flow around a TBM is elaborated, as well as grout flow along the lining. The calculated grout flow along the lining is compared with the results of measurements. Measurement data for the flow around the TBM are not available. Both the bentonite and the grout are modelled as a Bingham liquid and it will be shown that, due to the relatively low flow velocities, the yield stress is the governing parameter. The results of the calculations show that both the flow around the TBM and the flow around the lining may significantly influence loading on the TBM, the soil, and the lining. The bentonite and grout flow around the TBM may result in a lower volume loss than calculated when assuming that the soil follows the tapered TBM. The grout flow and especially grout consolidation lead to lower pressures around the lining if the tunnel is constructed in sandy soil. Der Bentonit- und Mörtelfluss um eine TBM und der Mörtelfluss entlang der Auskleidung werden diskutiert. Der berechnete Mörtelfluss entlang der Auskleidung wird mit Messdaten verglichen. Für die Strömungen um eine TBM existieren keine Messdaten. Sowohl der Bentonit als auch der Mörtel werden als Bingham Flüssigkeit modelliert, und es wird gezeigt, dass wegen der relativ niedrigen Strömungsgeschwindigkeiten die Fließspannung der bestimmende Parameter ist. Die Ergebnisse der Berechnungen zeigen, dass sowohl die Strömung um die TBM als auch entlang der Auskleidung einen bedeutenden Einfluss auf die Belastung der TBM, des Bodens und der Auskleidung haben. Der Bentonit- und Mörtelfluss um die TBM kann einen niedrigeren Volumenverlust zur Folge haben als berechnet, wenn man annimmt, dass der Boden der konisch zulaufenden TBM folgt. Der Mörtelfluss und besonders die Mörtelverfestigung führen zu einem niedrigeren Druck auf die Auskleidung wenn der Tunnel in sandigem Boden errichtet wird. [source] Cost-effectiveness of extended buprenorphine,naloxone treatment for opioid-dependent youth: data from a randomized trialADDICTION, Issue 9 2010Daniel Polsky ABSTRACT Aims The objective is to estimate cost, net social cost and cost-effectiveness in a clinical trial of extended buprenorphine,naloxone (BUP) treatment versus brief detoxification treatment in opioid-dependent youth. Design Economic evaluation of a clinical trial conducted at six community out-patient treatment programs from July 2003 to December 2006, who were randomized to 12 weeks of BUP or a 14-day taper (DETOX). BUP patients were prescribed up to 24 mg per day for 9 weeks and then tapered to zero at the end of week 12. DETOX patients were prescribed up to 14 mg per day and then tapered to zero on day 14. All were offered twice-weekly drug counseling. Participants 152 patients aged 15,21 years. Measurements Data were collected prospectively during the 12-week treatment and at follow-up interviews at months 6, 9 and 12. Findings The 12-week out-patient study treatment cost was $1514 (P < 0.001) higher for BUP relative to DETOX. One-year total direct medical cost was only $83 higher for BUP (P = 0.97). The cost-effectiveness ratio of BUP relative to DETOX was $1376 in terms of 1-year direct medical cost per quality-adjusted life year (QALY) and $25 049 in terms of out-patient treatment program cost per QALY. The acceptability curve suggests that the cost-effectiveness ratio of BUP relative to DETOX has an 86% chance of being accepted as cost-effective for a threshold of $100 000 per QALY. Conclusions Extended BUP treatment relative to brief detoxification is cost effective in the US health-care system for the outpatient treatment of opioid-dependent youth. [source] Impairment due to cannabis and ethanol: clinical signs and additive effectsADDICTION, Issue 6 2010Jørgen G. Bramness ABSTRACT Aims Studies have shown that the impairing effects of ,-9-tetrahydrocannabinol (THC) are dose-related. Cannabis intake increases the risk of traffic accidents. The purpose of this study was to see how different clinical tests and observations were related to blood THC concentrations and to determine whether the combined influence of THC and ethanol was different from either drug alone. Design A retrospective cross-sectional forensic database study. Setting Drivers apprehended by the police suspected of driving under the influence of alcohol other drugs. Participants We investigated 589 cases positive for THC only. In addition, 894 cases with THC and ethanol were included. A comparison was made with 3480 drivers with only ethanol in their blood and 79 drivers who tested negative. Measurements Data were analytical results of blood samples and the 27 clinical tests and observations included in the Norwegian clinical test for impairment (CTI). Findings No relationship was found between blood THC concentration and most of the CTI tests. Blood THC concentration was, however, related to conjunctival injection, pupil dilation and reaction to light and to the overall risk of being judged impaired. When THC and ethanol were detected together the risk of being judged impaired was increased markedly. Conclusions This study demonstrates that cannabis impairs driving ability in a concentration-related manner. The effect is smaller than for ethanol. The effect of ethanol and cannabis taken simultaneously is additive. Conjunctival injection, dilated pupils and slow pupil reaction are among the few signs to reveal THC influence. [source] The challenge of external validity in policy-relevant systematic reviews: a case study from the field of substance misuseADDICTION, Issue 1 2010Mark Pearson ABSTRACT Aim To critically evaluate the methods utilized in the conduct of a systematic review in the field of substance misuse Design Participant-observation in the review process, semi-structured interviews with review team members and management and structured observation of the process of guidance development. Setting An ,arm's-length' government body. Participants Review team members, management and the committee responsible for producing evidence-based guidance for policy and practice. Measurements Data from interviews and (participant-)observation were reflected upon critically in order to increase understanding of the systematic review process. Findings The application of systematic review methods produced an evidence base that did not inform the development of guidance to the extent that it could have done: (i) an emphasis upon internal research validity produced an evidence base with an emphasis on short-term interventions at the level of the individual; (ii) criteria for appraising the external validity of studies were not developed sufficiently; and (iii) the systematic review of evidence and development of guidance are strongly reliant upon the judgement of reviewers and committee members. Conclusions Prioritizing internal validity in a systematic review risks producing an evidence base that is not informed adequately by the wider determinants of health and which does not give sufficient consideration to external validity. The use of appropriate methods requires that commissioners of systematic reviews are clear at the outset how the review is proposed to be utilized. Review methods such as meta-ethnography and realist synthesis could contribute to making the frameworks within which judgements are made more explicit. [source] Gender and alcohol consumption: patterns from the multinational GENACIS projectADDICTION, Issue 9 2009Richard W. Wilsnack ABSTRACT Aims To evaluate multinational patterns of gender- and age-specific alcohol consumption. Design and participants Large general-population surveys of men's and women's drinking behavior (n's > 900) in 35 countries in 1997,2007 used a standardized questionnaire (25 countries) or measures comparable to those in the standardized questionnaire. Measurements Data from men and women in three age groups (18,34, 35,49, 50,65) showed the prevalence of drinkers, former drinkers, and lifetime abstainers; and the prevalence of high-frequency, high-volume, and heavy episodic drinking among current drinkers. Analyses examined gender ratios for prevalence rates and the direction of changes in prevalence rates across age groups. Findings Drinking per se and high-volume drinking were consistently more prevalent among men than among women, but lifetime abstention from alcohol was consistently more prevalent among women. Among respondents who had ever been drinkers, women in all age groups were consistently more likely to have stopped drinking than men were. Among drinkers, the prevalence of high-frequency drinking was consistently greatest in the oldest age group, particularly among men. Unexpectedly, the prevalence of drinking per se did not decline consistently with increasing age, and declines in high-volume and heavy episodic drinking with increasing age were more typical in Europe and English-speaking countries. Conclusions As expected, men still exceed women in drinking and high-volume drinking, although gender ratios vary. Better explanations are needed for why more women than men quit drinking, and why aging does not consistently reduce drinking and heavy drinking outside Europe and English-speaking countries. [source] The impact of changing nicotine replacement therapy licensing laws in the United Kingdom: findings from the International Tobacco Control Four Country SurveyADDICTION, Issue 8 2009Lion Shahab ABSTRACT Aim To evaluate the impact of a new licence for some nicotine replacement therapy products (NRT) for cutting down to stop (CDTS) on changes in the pattern of NRT use. Design Quasi-experimental design comparing changes in NRT use across two waves of a population-based, replenished-panel, telephone survey conducted before and after the introduction of new licensing laws in the United Kingdom with changes in NRT use in three comparison countries (Australia, Canada and United States) without a licensing change. Participants A total of 7386 and 7013 smokers and recent ex-smokers participating in the 2004 and/or 2006/7 survey. Measurements Data were collected on demographic and smoking characteristics as well as NRT use and access. In order to account for interdependence resulting from some participants being present in both waves, generalized estimation equations with an exchangeable correlation matrix were used to assess within-country changes and linear and logistic regressions to assess between-country differences in adjusted analyses. Findings NRT use was more prevalent in the United Kingdom and increased across waves in all countries but no wave × country interaction was observed. There was no evidence that the licensing change increased the prevalence of CDTS or the use of NRT (irrespective of how it was accessed) for CDTS in the United Kingdom relative to comparison countries. There was also no evidence for a change in concurrent smoking and NRT use among smokers not attempting to stop in the United Kingdom relative to comparison countries. Conclusion The addition of the CDTS licence for some NRT products in the United Kingdom appears to have had very limited, if any, impact on NRT use in the first year after the licence change. [source] Feasibility and validity of low-budget telephonic follow-up interviews in routine outcome monitoring of substance abuse treatmentADDICTION, Issue 7 2009Suzan C.C. Oudejans ABSTRACT Aims Routine outcome monitoring (ROM) is receiving growing attention. However, follow-up interviews are time-consuming and costly. This study examines the feasibility and validity of low-budget telephonic follow-up interviews for ROM in a substance abuse treatment centre (SATC). Design Observational study using data collected for routine outcome monitoring. Setting The study was performed in a SATC in an urban area in the Netherlands. Participants Feasibility and validity were assessed on data of 2325 patients. Measurements Data on pre-treatment socio-demographic and clinical characteristics were collected using electronic patient records (EPRs) and the European version of the Addiction Severity Index (EuropASI). Data on intensity of treatment were also collected through the EPRs. Telephonic follow-up interviews were conducted between 9 and 10 months after intake. Findings A 53% follow-up rate was achieved; 35% of the patients could not be contacted, 3% explicitly refused and in 8% other reasons accounted for non-participation. About 50% of the interviews took place in the intended time-frame. Costs were ,40 ($57) per completed interview. There were indications of selection bias, because patients with cocaine as their primary problem and patients with polysubstance abuse were under-represented in the follow-up sample; the presence of these disorders is associated with negative treatment outcome. Conclusions Implementing telephonic low-budget follow-up interviews for ROM is feasible, but selection bias threatens internal validity of data, limiting generalization to the total treatment population. Increased efforts to track patients for follow-up may improve generalization. [source] Drug use and perceived treatment need among newly sentenced prisoners in England and WalesADDICTION, Issue 2 2009Duncan Stewart ABSTRACT Aims To investigate pre-custody levels of drug use among newly sentenced prisoners and factors associated with perceived drug treatment need. Design, setting and participants A sample of 1457 prisoners was recruited to a general purpose longitudinal survey of convicted prisoners starting a new sentence. Measurements Data were collected by structured interviews on reception to prison. Measures were taken of illicit drug use, drug treatment history, current treatment needs, psychological health and a range of social problems. Findings Life-time use of heroin, crack cocaine, cocaine powder, amphetamines or cannabis was reported by 79% of prisoners. Cannabis was the drug reported most commonly, but approximately a third had used heroin or crack cocaine during the year before custody. Nearly half of recent drug users reported wanting help or support with a drug problem during their sentence. Dependence on heroin and cocaine, previous drug treatment, employment, accommodation and psychological health problems were all associated positively with perceived treatment need. Conclusions The prevalence of pre-custody drug use among this sample of newly sentenced prisoners was high. Because treatment need was associated with a range of drug, health and social factors, assessment and referral to appropriate interventions should occur as soon as possible on reception. Treatment should be coordinated with other services and support. [source] The Scalasca performance toolset architectureCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 6 2010Markus Geimer Abstract Scalasca is a performance toolset that has been specifically designed to analyze parallel application execution behavior on large-scale systems with many thousands of processors. It offers an incremental performance-analysis procedure that integrates runtime summaries with in-depth studies of concurrent behavior via event tracing, adopting a strategy of successively refined measurement configurations. Distinctive features are its ability to identify wait states in applications with very large numbers of processes and to combine these with efficiently summarized local measurements. In this article, we review the current toolset architecture, emphasizing its scalable design and the role of the different components in transforming raw measurement data into knowledge of application execution behavior. The scalability and effectiveness of Scalasca are then surveyed from experience measuring and analyzing real-world applications on a range of computer systems. Copyright © 2010 John Wiley & Sons, Ltd. [source] Damage identification of structures with uncertain frequency and mode shape dataEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 5 2002Yong Xia Abstract A statistical method with combined uncertain frequency and mode shape data for structural damage identification is proposed. By comparing the measured vibration data before damage or analytical finite element model of the intact structure with those measured after damage, the finite element model is updated so that its vibration characteristic changes are equal to the changes in the measured data as closely as possible. The effects of uncertainties in both the measured vibration data and finite element model are considered as random variables in model updating. The statistical variations of the updated finite element model are derived with perturbation method and Monte Carlo technique. The probabilities of damage existence in the structural members are then defined. The proposed method is applied to a laboratory tested steel cantilever beam and frame structure. The results show that all the damages are identified correctly with high probabilities of damage existence. Discussions are also made on the applicability of the method when no measurement data of intact structure are available. Copyright © 2002 John Wiley & Sons, Ltd. [source] Comparison of seven models for estimation of evapotranspiration and groundwater recharge using lysimeter measurement data in GermanyHYDROLOGICAL PROCESSES, Issue 18 2005C.-Y. Xu Abstract This study evaluates seven evapotranspiration models and their performance in water balance studies by using lysimeter measurement data at the Mönchengladbach hydrological and meteorological station in Germany. Of the seven evapotranspiration models evaluated, three models calculate actual evapotranspiration directly using the complementary relationship approach, i.e. the CRAE model of Morton, the advection,aridity (AA) model of Brutsaert and Stricker, and the GG model of Granger and Gray, and four models calculate first potential evapotranspiration and then actual evapotranspiration by considering the soil moisture condition. Two of the four potential evapotranspiration models belong to the temperature-based category, i.e. the Thornthwaite model and the Hargreaves model, and the other two belong to the radiation-based category, i.e. the Makkink model and the Priestley,Taylor model. The evapotranspiration calculated by the above seven models, together with precipitation, is used in the water balance model to calculate other water balance components. The results show that, for the calculation of actual evapotranspiration, the GG model and the Makkink model performed better than the other models; for the calculation of groundwater recharge using the water balance approach, the GG model and the AA models performed better; for the simulation of soil moisture content using the water balance approach, four models (GG, Thornthwaite, Makkink and Priestley,Taylor) out of the seven give equally good results. It can be concluded that the lysimeter-measured water balance components, i.e. actual evapotranspiration, groundwater recharge, soil moisture, etc., can be predicted by the GG model and the Makkink model with good accuracy. Copyright © 2005 John Wiley & Sons, Ltd. [source] Factors governing the formation and persistence of layers in a subalpine snowpackHYDROLOGICAL PROCESSES, Issue 7 2004David Gustafsson Abstract The layered structure of a snowpack has a great effect on several important physical processes, such as water movement, reflection of solar radiation or avalanche release. Our aim was to investigate what factors are most important with respect to the formation and persistence of distinct layers in a subalpine environment. We used a physically based numerical one-dimensional model to simulate the development of a snowpack on a subalpine meadow in central Switzerland during one winter season (1998,99). A thorough model validation was based on extensive measurement data including meteorological and snow physical parameters. The model simulated the snow water equivalent and the depth of the snowpack as well as the energy balance accurately. The observed strong layering of the snowpack, however, was not reproduced satisfactorily. In a sensitivity analysis, we tested different model options and parameter settings significant for the formation of snow layers. The neglection of effects of snow microstructure on the compaction rate, and the current description of the water redistribution inside the snowpack, which disregard capillary barrier effects, preferential flow and lateral water flow, were the major limitations for a more realistic simulation of the snowpack layering. Copyright © 2004 John Wiley & Sons, Ltd. [source] Geotechnical parameter estimation in tunnelling using relative convergence measurementINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 2 2006Kook-Hwan Cho Abstract Accurate estimation of geotechnical parameters is an important and difficult task in tunnel design and construction. Optimum evaluation of the geotechnical parameters have been carried out by the back-analysis method based on estimated absolute convergence data. In this study, a back-analysis technique using measured relative convergence in tunnelling is proposed. The extended Bayesian method (EBM), which combines the prior information with the field measurement data, is adopted and combined with the 3-dimensional finite element analysis to predict ground motion. By directly using the relative convergence as observation data in the EBM, we can exclude errors that arise in the estimation of absolute displacement from measured convergence, and can evaluate the geotechnical parameters with sufficient reliability. The proposed back-analysis technique is applied and validated by using the measured data from two tunnel sites in Korea. Copyright © 2005 John Wiley & Sons, Ltd. [source] Back analysis of model parameters in geotechnical engineering by means of soft computingINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 14 2003B. Pichler Abstract In this paper, a parameter identification (PI) method for determination of unknown model parameters in geotechnical engineering is proposed. It is based on measurement data provided by the construction site. Model parameters for finite element (FE) analyses are identified such that the results of these calculations agree with the available measurement data as well as possible. For determination of the unknown model parameters, use of an artificial neural network (ANN) is proposed. The network is trained to approximate the results of FE simulations. A genetic algorithm (GA) uses the trained ANN to provide an estimate of optimal model parameters which, finally, has to be assessed by an additional FE analysis. The presented mode of PI renders back analysis of model parameters feasible even for large-scale models as used in geotechnical engineering. The advantages of theoretical developments concerning both the structure and the training of the ANN are illustrated by the identification of material properties from experimental data. Finally, the performance of the proposed PI method is demonstrated by two problems taken from geotechnical engineering. The impact of back analysis on the actual construction process is outlined. Copyright © 2003 John Wiley & Sons, Ltd. [source] Distribution learning for radio network planning tool simulationINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 12 2008Z. Nouir Abstract We propose a novel method that combines the simulation results of a model-based prediction tool with the knowledge contained in measurement data. This mixture of the a priori information and the posteriori knowledge aims at enhancing the prediction results by increasing their precision and quality. A multilayer perceptron (MLP) is trained to learn the mapping between the distributions of the measurement data and the simulation data. To make the complexity of the MLP tractable, we propose the utilization of independent component analysis (ICA). The ICA transformation makes the variables at the input of the MLP statistically independent so that it can perform its learning and generalization on individual one-dimensional distributions. Other contributions consist of the application of the k -means clustering algorithm on the incoming data and the use of the training data world model to enhance the generalization capability of the MLP. The world model consists of the aggregation of all the available data in the learning space. The proposed method is applied to a third generation mobile network to enhance the predictions of uplink and downlink base station loads. After a training performed on a given network configuration, mechanical antenna tilts are modified and we show that the results obtained by the supervised predictions are much closer to measurements than simulation results for cases that have not been encountered before. Copyright © 2008 John Wiley & Sons, Ltd. [source] Weighting methodologies in multi-criteria evaluations of combined heat and power systemsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 12 2009Jiang-Jiang Wang Abstract Several combined heat and power (CHP) system options are presented to assess and compare with respect to the end users' requirements. According to the obtained data from literature, 16 kinds of CHP systems are evaluated using gray relational method in multi-criteria, such as technology, economy, environment, and society. The results depend greatly on the criteria weights in multi-criteria evaluations. Aiming to obtain rational result, this paper reviews the weighting method briefly and proposes an optimal combined weighting method to consider the subjectivity of decision-maker and the objectivity of measurement data. The singular value decomposition aggregation method is employed to verify the rationality of evaluation result. Through multi-criteria evaluation and discussions, the combination weighting method is recommended to be used in the selection of CHP schemes. Finally, the best CHP system is selected and the most conspicuous factors having great impact on CHP system with respect to the users' requirements are given out. Copyright © 2009 John Wiley & Sons, Ltd. [source] Simplified models for the performance evaluation of desiccant wheel dehumidificationINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 1 2003M. Beccali Abstract In the present communication, simple models have been presented to evaluate the performance of rotary desiccant wheels based on different kind of solid desiccants e.g. silica gel and LiCl. The first part of the paper presents ,Model 54' which is developed for silica gel desiccant rotor. The model has been derived from the interpolation of experimental data obtained from the industry and the correlations have been developed for predicting outlet temperature and absolute humidity. The ,Model 54' consists of 54 coefficients corresponding to each correlation for outlet absolute humidity and temperature and it is found that the model predicts very well the performance of silica gel desiccant rotor (Type-I). In the second part of the paper, a psychrometric model has been presented to obtain relatively simple correlations for outlet temperature and absolute humidity. The developed psychometric model is based on the correlations between the relative humidity and enthalpy of supply and regeneration air streams. The model is used to predict the performance of three type of desiccant rotors manufactured by using different kind of solid desiccants (Type I, II and III). The model is tested corresponding to a wide range of measurement data. The developed psychometric model is simple in nature and able to predict very well the performance of different kind of desiccant rotors. Copyright © 2002 John Wiley & Sons, Ltd. [source] Incremental identification of fluid multi-phase reaction systemsAICHE JOURNAL, Issue 4 2009Claas Michalik Abstract Despite their importance, rigorous process models are rarely available for reaction and especially multi-phase reaction systems. The high complexity of these systems, which is due to the superposed effects of mass transfer and intrinsic reaction, is the major barrier for the development of process models. A methodology that allows thesystematic decomposition of mass transfer and chemical reaction and thus enables the efficient identification of multi-phase reaction systems is proposed in this work. The method is based on the so-called Incremental Identification Method, recently presented by Brendel et al., Chem Eng Sci. 2006;61:5404-5420. The method allows to easily test the identifiability of a system based on the available measurement data. If identifiability is given, the intrinsic reaction kinetics can be identified in a sound and numerically robust manner. These benefits are illustrated using a simulated 2-phase enzyme reaction system. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Fault detection in nonlinear continuous-time systems with uncertain parametersAICHE JOURNAL, Issue 9 2008Youdong Lin Abstract In model-based fault diagnosis for dynamic systems with uncertain parameters, an envelope of all fault-free behaviors can be determined from the model and used as a reference for detecting faults. We demonstrate here a method for generating an envelope that is rigorously guaranteed to be complete, but without significant overestimation. The method is based on an interval approach, but uses Taylor models to reduce the overestimation often associated with interval methods. To speed fault detection, a method that uses bounded-error measurement data and a constraint propagation procedure is proposed for shrinking the envelope. Several fault detection scenarios involving nonlinear, continuous-time systems are used to evaluate this approach. © 2008 American Institute of Chemical Engineers AIChE J, 2008 [source] Influence of bone density on the cement fixation of femoral hip resurfacing componentsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 8 2010Rudi G. Bitsch Abstract In clinical outcome studies, small component sizes, female gender, femoral shape, focal bone defects, bad bone quality, and biomechanics have been associated with failures of resurfacing arthroplasties. We used a well-established experimental setup and human bone specimens to analyze the effects of bone density on cement fixation of femoral hip resurfacing components. Thirty-one fresh frozen femora were prepared for resurfacing using the original instruments. ASRÔ resurfacing prostheses were implanted after dual-energy X-ray densitometer scans. Real-time measurements of pressure and temperature during implantation, analyses of cement penetration, and measurements of micro motions under torque application were performed. The associations of bone density and measurement data were examined calculating regression lines and multiple correlation coefficients; acceptability was tested with ANOVA. We found significant relations between bone density and micro motion, cement penetration, cement mantle thickness, cement pressure, and interface temperature. Mean bone density of the femora was 0.82,±,0.13,g/cm2, t- score was ,0.7,±,1.0, and mean micro motion between bone and femoral resurfacing component was 17.5,±,9.1,µm/Nm. The regression line between bone density and micro motion was equal to ,56.7,×, bone density,+,63.8, R,=,0.815 (p,<,0.001). Bone density scans are most helpful for patient selection in hip resurfacing, and a better bone quality leads to higher initial component stability. A sophisticated cementing technique is recommended to avoid vigorous impaction and incomplete seating, since increasing bone density also results in higher cement pressures, lower cement penetration, lower interface temperatures, and thicker cement mantles. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:986,991, 2010 [source] Online estimation and control of polymer quality in a copolymerization reactorAICHE JOURNAL, Issue 5 2002Myung-June Park The validity of an online state estimator for a semi-batch MMA/MA solution copolymerization reactor was established using online densitometer and viscometer. Using the conventional extended Kalman filter (EKF) as the state estimator, the experiment was conducted under both isothermal and nonisothermal conditions for application to the control of copolymer properties. Further analysis was made by using ofline measurement data for the mol fraction of MMA in the remaining monomers and the solid content. The EKF was found to provide a good estimate for the state of the copolymerization system. A model predictive controller was designed and implemented to obtain copolymers with uniform copolymer composition and the desired weight average molecular weight by adopting the feed flow rate of MMA and the reaction temperature as control inputs. The controller was proven effective with a satisfactory performance for the control of polymer properties in the semi-batch copolymerization reactor. [source] 3D EIT for breast cancer imaging: System, measurements, and reconstructionMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2008Gang Ye Abstract Electrical impedance tomography (EIT) is a developing imaging modality for early detection of breast cancer. In an EIT system, a low-frequency current is applied sequentially between different electrode pairs while voltage measurements are made at other electrodes to arrive at the electrical impedance values. The set of impedance measurement data is then computed to produce a 3D electrical conductivity map of the volume to be imaged. In this work, the design, measurements, and inversion of a full 3D EIT system are discussed. Experimentally determined EIT images of phantom objects are presented. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3261,3271, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23932 [source] Analysis of characteristics of a U-slot patch antenna using finite-difference time-domain methodMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 9 2006Hsing-Yi Chen Abstract The finite-difference time domain (FDTD) method is successfully used to analyze characteristics of a U-slot patch antenna without using commercial software packages such as HFSS, IE3D, and CST. The method is proved to be an efficient tool for deep insight studies on complicated patch antennas. Numerical results of return loss, radiation pattern, current distribution, and antenna efficiency are presented. FDTD results are also compared with measurement data and shown to be in good agreement. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1687,1694, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21804 [source] A reduced-order stochastic observer approach to optimal state estimation with noise-free measurementsOPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 3 2001Edwin Engin Yaz Abstract In a continuous-time Kalman filter, it is required that the measurement noise covariance be non-singular. If the measurements are noise-free, then this condition does not hold and, in practice, the measurement data are differentiated to define a derived measurement function to build what is known as Deyst filter. It is proposed here that a reduced-order observer be used in deriving the linear minimum-variance filter to construct state estimates based on the original measurement data with no need for differentiation. This filter is of dimension (n,p) where n and p are the state and measurement vector dimensions, respectively. In this work, we consider both the finite-time and infinite-time results. The set of all assignable estimation error covariances are characterized and the set of all estimator gains are parametrized in addition to the linear minimum variance optimal results. The conditions for the existence of the optimal steady-state filter are obtained in terms of the system theoretic properties of the original signal model. A simple example is included to illustrate the effectiveness of the proposed technique. Copyright © 2001 John Wiley & Sons, Ltd. [source] Robust Isolation Of Sensor FailuresASIAN JOURNAL OF CONTROL, Issue 1 2003R. Xu ABSTRACT Sensor self-validity check is a critical step in system control and fault diagnostics. In this paper, a robust approach to isolate sensor failures is proposed. First, a residual model for a given system is built off-line and directly based on input-output measurement data. The residual model outputs are called "primary residuals" and are zero when there is no fault. Most conventional approaches to residual model generation are indirect, as they first require the determination of state-space or other models using standard system identification algorithms. Second, a new max-min design of structured residuals, which can maximize the sensitivity of structured residuals with respect to sensor failures, is proposed. Based on the structured residuals, one can then isolate the sensor failures. This design can also be done in an off-line manner. It is an optimization procedure that avoids local optimal solutions. Simulation and experimental results demonstrated the effectiveness of the proposed method. [source] Wireless network analysis using per call measurement dataBELL LABS TECHNICAL JOURNAL, Issue 4 2007Michael J. Flanagan The advent of per call measurement data (PCMD) in Alcatel-Lucent network products has enabled an unprecedented view into code division multiple access (CDMA) network operation at the subscriber level. The timing information available in PCMD records allows for maximum-likelihood estimation of subscriber locations using experimental geo-location analysis software suite (GLASS) tools developed at Alcatel-Lucent. Spatial variations of traffic densities, lost call densities, and other phenomena can now be readily studied to better understand wireless network operation as experienced by subscribers. These types of tools can also incorporate financial and business details regarding subscribers to guide network operation and optimization activities more effectively. © 2007 Alcatel-Lucent. [source] Temporal trends and misclassification in residential 60 Hz magnetic field measurementsBIOELECTROMAGNETICS, Issue 3 2002Robert S. Banks Abstract This research addressed the question of how well measurement data collected during a single visit, made at an arbitrary hour of day, day of week, and season, estimate longer term residential 60 Hz magnetic field levels. We made repeat spot and 24 h measurements in 51 children's home, located in the Detroit, MI, and the Minneapolis-St. Paul, MN metropolitan areas, on a regular bimonthly schedule over a 1 year period, as well as a single 2 week measurement, for total of eight visits, producing 21 days of data for each residence. We defined the long term estimate (LTE) as the geometric mean of all available 24 h geometric means from the first six bimonthly visits. The LTE served as the reference level for assessing seasonal, day of week, and diurnal effects, as well as the potential for misclassification. We found a small, but statistically significant (P,<,.05), seasonal effect, with levels approximately 3% lower than the LTE in the spring and about 4% greater during the summer. No effect was found for day of week. However, we did find a systematic and appreciable diurnal effect, suggesting that, for example, an evening spot measurement may overestimate the LTE by 20% or more. We also assessed how well the 24 h measurement from the last visit, which was not used in calculation of the LTE, estimated the LTE. We found a high degree of correlation (r,=,.92) and fair to good agreement using four exposure categories (,,=,.53). Thus, the 24 h measurement appears to be a satisfactory LTE estimator. However, this finding must be interpreted with caution since considerable unexplained variability was present among the repeat 24 h measurements in about one-third of the homes. While the 2 week measurement does somewhat decrease exposure misclassification, its added intrusiveness and cost are likely to outweigh the improved precision. Bioelectromagnetics 23:196,205, 2002. © 2002 Wiley-Liss, Inc. [source] Analysis of Escherichia coli anaplerotic metabolism and its regulation mechanisms from the metabolic responses to altered dilution rates and phosphoenolpyruvate carboxykinase knockoutBIOTECHNOLOGY & BIOENGINEERING, Issue 2 2003Chen Yang Abstract The gluconeogenic phosphoenolpyruvate (PEP) carboxykinase is active in Escherichia coli during its growth on glucose. The present study investigated the influence of growth rates and PEP carboxykinase knockout on the anaplerotic fluxes in E. coli. The intracellular fluxes were determined using the complementary methods of flux ratio analysis and metabolic flux analysis based on [U- 13C6]glucose labeling experiments and 2D nuclear magnetic resonance (NMR) spectroscopy of cellular amino acids and glycerol. Significant activity of PEP carboxykinase was identified in wild-type E. coli, and the ATP dissipation for the futile cycling via this reaction accounted for up to 8.2% of the total energy flux. Flux analysis of pck deletion mutant revealed that abolishment of PEP carboxykinase activity resulted in a remarkably reduced flux through the anaplerotic PEP carboxylase and the activation of the glyoxylate shunt, with 23% of isocitrate found being channeled in the glyoxylate shunt. The changes in intracellular metabolite concentrations and specific enzyme activities associated with different growth rates and pck deletion, were also determined. Combining the measurement data of in vivo fluxes, metabolite concentrations and enzyme activities, the in vivo regulations of PEP carboxykinase flux, PEP carboxylation, and glyoxylate shunt in E. coli are discussed. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 84: 129,144, 2003. [source] The common G-allele of interleukin-18 single-nucleotide polymorphism is a genetic risk factor for atopic asthma.CLINICAL & EXPERIMENTAL ALLERGY, Issue 2 2006The SAPALDIA Cohort Study Summary Background IL-18 is a pleiotrophic cytokine involved in both, T-helper type 1 (Th1) and Th2 differentiation. Recently genetic variants in the IL-18 gene have been associated with increased risk of atopy and asthma. Objective To examine the relationship of a genetic, haplotype-tagging promotor variant ,137G/C in the IL-18 gene with atopic asthma in a large, well-characterized and population-based study of adults. Methods Prospective cohort study design was used to collect interview and biological measurement data at two examination time-points 11 years apart. Multivariate logistic regression analysis was used to assess the association of genotype with asthma and atopy. Results The G-allele of the IL-18 promotor variant (,137G/C) was associated with a markedly increased risk for the prevalence of physician-diagnosed asthma with concomitant skin reactivity to common allergens. Stratification of the asthma cases by skin reactivity to common allergens revealed an exclusive association of IL-18 ,137 G-allele with an increased prevalence of atopic asthma (adjusted odds ratio (OR): 3.63; 95% confidence interval: (1.64,8.02) for GC or GG carriers vs. CC carriers), and no according association with asthma and concomitant negative skin reactivity (adjusted OR: 1.13; 0.66,1.94). The interaction between IL-18 ,137G/C genotype and positive skin prick test was statistically significant (P=0.029). None of 74 incident asthma cases with atopy at baseline exhibited the CC genotype. Conclusion Our results strongly suggest that this variant of the IL-18 gene is an important genetic determinant involved in the development of atopic asthma. [source] Anatomy of the lateral femoral cutaneous nerve related to inguinal ligament, adjacent bony landmarks, and femoral arteryCLINICAL ANATOMY, Issue 8 2008Porames Doklamyai Abstract Lateral femoral cutaneous nerve (LFCN) generally emerges from the pelvis behind the inguinal ligament (IL) to the thigh. Because of its proximity to the anterior superior iliac spine (ASIS) and hip joint, the LFCN is prone to injuries during various procedures. Anatomy of this nerve is highly variable among studies. Moreover, measurement data regarding its branches including the differences between genders and sides are still lacking. This study was, therefore, done to clarify these issues. Eighty-five thighs from 43 cadavers of both genders were dissected at the inguinal region. Distances from each branch of the LFCN to palpable landmarks: the ASIS, pubic tubercle (PT) and femoral artery (FA) were measured along the IL. Up to four branches of the LFCN were found; however, the single trunk was the most common form (>65%). The common site of this pattern on the IL was within 2 cm medial to the ASIS but could be present at over 6 cm. The distances in case of bifurcation were mostly comparable to those of the single trunk. In contrast, the values varied considerably in the cases with three or more branches (three cases). Regarding side and gender, asymmetry in the branching pattern was found in one fourth of specimens. However, only some minor differences between genders or sides in the measurement data were seen. These findings suggest that asymmetry and multiple branches of the LFCN should be concerned. The measurement data are also useful for localizing the LFCN with higher accuracy. Clin. Anat. 21:769,774, 2008. © 2008 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||||||||