bluuebunny/crossref_metadata_2025 huggingface dataset:
Welding Distortion Minimization for an Aluminum Alloy Extruded Beam Structure Using a 2D Model
Authors: Nnaji Bart O. , Gupta Deepak , Kim Kyoung-Yun
Published: March 2004

Optimization of the weld sequence of a sub-assembly composed of thin walled aluminum alloy extruded beams is investigated and presented. The main factor considered is the quality of the assembly after welding, which is measured by the deformation behavior at pre-defined critical locations. The aluminum alloy extruded beam structure is simplified by a 2-D beam element model. Our methodology consists of applying pre-estimated angular shrinkages for each welding step thus eliminating use of a complex nonlinear transient analysis which would require consideration of thermo-mechanical interactions and plasticity. Two distortion modes (angular shrinkage and tilting shrinkage) are investigated and applied to model welding distortion. Different criteria for minimization of welding distortion have been investigated, such as overall deformation or weighted deformation with emphasis on some critical areas. A composite quality index is formulated, which is a weighted measure of critical deformation and the overall deformation. For simulating welding deformation and the role of sequences, some weld sequences were selected heuristically and they were simulated in ANSYS 5.2. Based on the quality index of these sequences, some were reproduced while mutating other portions of these sequences to find better sequences. Finally, deformation data for each node and weighted measures of deformation for considered sequences are presented, and final deformed shapes for different sequences, maximum principal stress, and bending moment across the beams are shown graphically.
Flank Wear and Process Characteristic Effect on System Dynamics in Turning
Authors: Lu Ming-Chyuan , Kannatey-Asibu, Elijah
Published: March 2004

The dynamics of the cutting process is modeled for investigating the relationship between tool wear and sound generation during surface turning. The vibration of the tool holder, together with the cutting insert, is considered as the main source of sound associated with tool wear. In this research, the tool holder-cutting insert combination is simplified as a cantilever beam which is excited by an external force that is directly related to tool wear. Based on this model, the displacement of the cutting tool is shown to be directly affected by tool wear and process characteristics. Simulation results show a change in the sound signal distribution over frequency as tool wear increases. A transfer function that includes the process characteristics is also developed to investigate the capability of sound and vibration signals in tool wear monitoring for a specific process. This provides critical information for sensor selection in implementing a tool failure monitoring system in reconfigurable manufacturing.
Modelling Powder Concentration Distribution From a Coaxial Deposition Nozzle for Laser-Based Rapid Tooling
Authors: Pinkerton Andrew J. , Li Lin
Published: March 2004

Direct laser deposition is a solid freeform fabrication process that is capable of producing fully dense components with full structural integrity and is greatly enhanced by the use of an omnidirectional coaxial powder nozzle to supply the build material. In order to optimize the technique, accurate control of the two critical operational parameters of material feed rate and incident laser power intensity is necessary. Both parameters are affected by the axial powder stream concentration between the nozzle and the deposition point. In this work, a mathematical model for the powder concentration distribution is developed and the results from it compared with an experimental investigation using optical and image analysis techniques. The two show good agreement. The application of the model to the evaluation of nozzle geometry and the calculation of laser beam attenuation are demonstrated.
Framework for Cone Feature Measurement Using Coordinate Measuring Machines
Authors: Prakasvudhisarn Chakguy , Raman Shivakumar
Published: March 2004

Complex forms such as conicity have been largely ignored in the coordinate form literature, in spite of the sufficient need to inspect them in parts such as tapered rollers in bearings. This paper attempts to develop guidelines for inspection of cones and conical frustums using probe-type coordinate measuring machines. The sampling problem, the path determination, and fitting of form zones are each addressed in detail. Moreover, an integrative approach is taken for form verification and detailed experimental analysis is conducted as a pilot study for demonstrating the need for the same. Three separate sampling methods are applied: Hammersley, Halton-Zaremba, and Aligned Systematic; at various sample sizes using sampling theory and prior work in two-dimensional sampling. Linear and nonlinear deviations are formulated using optimization and least-squared methods and solved to yield competitive solutions. Comprehensive experimental analysis investigated issues of model adequacy, nesting, interactions, and individual effects, while studying conicity as a response variable in the light of sampling strategies, sizes, cone surface areas, and fitting methods. In summary, an orderly framework for sampling and fitting cones is developed which can lead to the development of comprehensive standards and solutions for industry.
Modeling of CBN Tool Flank Wear Progression in Finish Hard Turning
Authors: Huang Yong , Liang Steven Y.
Published: March 2004

Cubic Boron Nitride (CBN) cutters are widely used in finish turning of hardened parts. Their wear mechanisms and associated wear rates are important issues to be understood in view of the high cost of CBN cutters and because of the tool change down-time cost which impacts the economic justification of CBN precision hard turning. The objective of this study is to present a methodology to analytically model the CBN tool flank wear rate as a function of tool/workpiece material properties, cutting parameters and process arrangement in three-dimensional finish hard turning. The proposed model is calibrated with experimental data of finish turning of hardened 52100 bearing steel with a CBN insert, and further validated over practical hard turning conditions. It is shown that adhesion is the main wear mechanism over common cutting conditions, which agrees with documented observations, however, chemical diffusion can gain dominance over extended periods of machining time under aggressive cutting conditions.
Integrated Dynamic Thermo-Mechanical Modeling of High Speed Spindles, Part 1: Model Development
Authors: Li Hongqi , Shin Yung C.
Published: March 2004

This paper presents a comprehensive integrated thermo-dynamic model for various high speed spindles. The entire model consists of fully coupled three sub-models: bearing, spindle dynamic and thermal models. Using a finite element approach, a new thermal model has been generated, which can describe complex structures of high-speed motorized spindles, and can predict more accurate temperature distributions. The spindle dynamic model is constructed using finite elements based on Timoshenko beam theory and has been improved by considering shear deformation, material and bearing damping, and the spindle/tool-holder interface. Using the new thermo-dynamic model, more general and detailed bearing configurations can be modeled through a systematic coupling procedure. The thermal expansions of the shaft, housing and bearings are calculated based on predicted temperature distributions and are used to update the bearing preloads depending on the operating conditions, which are again used to update the thermal model. Therefore, the model is fully integrated and can provide solutions in terms of all the design parameters and operating conditions.
Thermal Aspects of Grinding With Electroplated CBN Wheels
Authors: Upadhyaya R. P. , Malkin S.
Published: March 2004

An investigation is reported on the thermal aspects of grinding with single layer electroplated CBN wheels. The topography of these wheels is not periodically restored by dressing or truing, so the grinding behavior progressively changes as the wheel wears down. Straight surface grinding experiments were conducted to determine the effect of wheel wear and fluid flow on the grinding temperatures and energy partition. Low energy partition values of 3%–8% were obtained at temperatures below the fluid burnout limit. The energy partition results were analyzed in terms of a topographical analysis of the wheel surface and a thermal model which accounts for the removal of heat at the grinding zone by conduction to the abrasive grains and to the grinding fluid.
Singularity Issues in Fixture Fault Diagnosis for Multi-Station Assembly Processes
Authors: Ding Yu , Gupta Abhishek , Apley Daniel W.
Published: March 2004

This paper presents a method of diagnosing variance components of process error sources in singular manufacturing systems. The singularity problem is studied and the cause examined in the context of fixture error diagnosis in multi-station assembly processes. The singularity problem results in nondiagnosable fixture errors when standard least-squares (LS) estimation methods are used. This paper suggests a reformulation of the original error propagation model into a covariance relation. The LS criterion is then applied directly to the sample covariance matrix to estimate the variance components. Diagnosability conditions for this variance LS estimator are derived, and it is demonstrated that certain singular systems that are not diagnosable using traditional LS methods become diagnosable with the variance LS estimator. Modified versions that improve the accuracy of the variance LS estimator are also presented. The various procedures are thoroughly contrasted, in terms of accuracy and diagnosability. The results are illustrated with examples from panel assembly, although the application of the approach and the conclusions extend to more general discrete-part manufacturing processes where fixtures are used to ensure dimensional accuracy of the final product.
A Computational and Experimental Study of Cold Rolling of Aluminum Alloys With Edge Cracking
Authors: Ghosh S. , Li M. , Gardiner D.
Published: March 2004

This paper identifies various modeling issues that are necessary for successful simulation of the cold rolling process by comparing it with experiments on aluminum alloys. It combines considerable experimental studies with finite element simulations using the ABAQUS/Explicit commercial finite element code to identify and evaluate modeling parameters, such as the material properties and friction laws. Damage models are incorporated in the numerical simulations by using plasticity with damage variables e.g., the Gurson-Tvergaard model with evolving porosity and Cockcroft-Latham with damage in terms of plastic work. The 3D model predictions are compared with predictions from 2D models to understand the limitations of 2D simulations in predicting the stresses, strains and evolving damage in the rolled strip.
Microscale Laser Shock Peening of Thin Films, Part 2: High Spatial Resolution Material Characterization
Authors: Zhang Wenwu , Yao Y. Lawrence , Noyan I. C.
Published: March 2004

Microscale Laser Shock Peening (LSP) is a technique that can be potentially applied to manipulate the residual stress distributions in metal film structures and thus improve the reliability of micro-devices. This paper reports high-spatial-resolution characterization of shock treated copper thin films on single-crystal silicon substrates, where scanning x-ray microtopography is used to map the relative variation of the stress/strain field with micron spatial resolution, and instrumented nanoindentation is applied to measure the distribution of hardness and deduce the sign of the stress/strain field. The measurement results are also compared with 3-D simulation results. The general trends in simulations agree with those from experimental measurements. Simulations and experiments show that there is a near linear correlation between strain energy density at the film-substrate interface and the X-ray diffraction intensity contrast.
Predicting the Effects of Overloads on Fatigue Crack Growth in an Al-SiC MMC Using a Computational Model
Authors: Bruzzi M. S. , McHugh P. E.
Published: March 2004

A defect tolerant approach to fatigue modeling for constant amplitude loading was developed by Bruzzi and McHugh (2002) and applied to two metal matrix composites: (1) a forged 2124 Al reinforced with 17 percent SiC particles and (2) a cast 359 Al reinforced with 20 percent SiC particles MMC in Bruzzi and McHugh (2003). In reality, however, engineering components are invariably subjected to varying cyclic stress amplitudes. In order to investigate the suitability of extending the fatigue modelling approach developed to variable amplitude loading, the effects of single and periodic peak tensile overloads are investigated in this work for the case of the Al 2124 MMC. The effects of overloads in causing significant changes to the level of closure in the wake of the crack tip, following the overload, in addition to changes in the nominally applied stress amplitude are firstly discussed in an overview. The quantification of the effects of overloads by use of experimental “resistance to crack growth curves” and the extension of the fatigue modeling approach to account for these effects are then described and investigated. Finally the predicted results of the impact of overloads on the short crack growth behavior of the Al 2124 MMC are presented and discussed. The extension of the fatigue modeling approach to account for the effects of overloads provides an additional means of validating the modelling approach developed by Bruzzi and McHugh (2002, 2003).
Dynamic Compressive Behavior of EPDM Rubber Under Nearly Uniaxial Strain Conditions
Authors: Song B. , Chen W.
Published: March 2004

Dynamic compressive stress-strain curves for ethylene-propylene-diene monomer (EPDM) rubber at various strain rates under nearly uniaxial strain conditions have been determined with a pulse-shaped split Hopkinson pressure bar (SHPB). The resultant stress-strain curves exhibited significantly nonlinear behavior, with strong sensitivities to strain rates. The dynamic stresses in the EPDM rubber at certain strains under uniaxial strain conditions increased significantly as compared to those under uniaxial stress conditions. A strain-rate-dependent material model, including a strain-rate-sensitive term, has been developed through a strain-energy function for compressible Mooney-Rivlin hyperelastic solids. The model provided a good description of the compressive axial stress-strain response of the EPDM rubber at various strain rates under uniaxial strain conditions.
A Molecular Elevator
Authors: Badjić Jovica D. , Balzani Vincenzo , Credi Alberto , Silvi Serena , Stoddart J. Fraser
Published: March 2004

We report the incrementally staged design, synthesis, characterization, and operation of a molecular machine that behaves like a nanoscale elevator. The operation of this device, which is made of a platformlike component interlocked with a trifurcated riglike component and is only 3.5 nanometers by 2.5 nanometers in size, relies on the integration of several structural and functional molecular subunits. This molecular elevator is considerably more complex and better organized than previously reported artificial molecular machines. It exhibits a clear-cut on-off reversible behavior, and it could develop forces up to around 200 piconewtons.
Effectiveness of targeted falls prevention programme in subacute hospital setting: randomised controlled trial
Authors: Haines Terry P , Bennell Kim L , Osborne Richard H , Hill Keith D
Published: March 2004

Objective To assess the effectiveness of a targeted, multiple intervention falls prevention programme in reducing falls and injuries related to falls in a subacute hospital.

Design Randomised controlled trial of a targeted multiple intervention programme implemented in addition to usual care compared with usual care alone.

Setting Three subacute wards in a metropolitan hospital specialising in rehabilitation and care of elderly patients.

Participants 626 men and women aged 38 to 99 years (average 80 years) were recruited from consecutive admissions to subacute hospital wards.

Intervention Falls risk alert card with information brochure, exercise programme, education programme, and hip protectors.

Main outcome measures Incidence rate of falls, injuries related to falls, and proportion of participants who experienced one or more falls during their stay in hospital.

Results Participants in the intervention group (n = 310) experienced 30% fewer falls than participants in the control group (n = 316). This difference was significant (Peto log rank test P = 0.045) and was most obvious after 45 days of observation. In the intervention group there was a trend for a reduction in the proportion of participants who experienced falls (relative risk 0.78, 95% confidence interval 0.56 to 1.06) and 28% fewer falls resulted in injury (log rank test P = 0.20).

Conclusions A targeted multiple intervention falls prevention programme reduces the incidence of falls in the subacute hospital setting.
A case-crossover study of transient risk factors for occupational acute hand injury
Authors: Sorock G S , Lombardi D A , Hauser R , Eisen E A , Herrick R F , Mittleman M A
Published: March 2004

Background:Workers with acute hand injuries account for over 1 000 000 emergency department visits annually in the United States.

Aims:To determine potential transient risk factors for occupational acute hand injury.

Methods:Subjects were recruited from 23 occupational health clinics in five northeastern states in the USA. In a telephone interview, subjects were asked to report the occurrence of seven potential risk factors within a 90-minute time period before an acute hand injury. Each case also provided control information on exposures during the month before the injury. The self-matched feature of the study design controlled for stable between-person confounders.

Results:A total of 1166 subjects were interviewed (891 men, 275 women), with a mean age (SD) of 37.2 years (11.4). The median time interval between injury and interview was 1.3 days. Sixty three per cent of subjects had a laceration. The relative risk of a hand injury was increased when working with equipment, tools, or work pieces not performing as expected (11.0, 95% CI 9.4 to 12.8), or when using a different work method to do a task (10.5, 95% CI 8.7 to 12.7). Other transient factors in decreasing order of relative risk were doing an unusual task, being distracted, and being rushed. Wearing gloves reduced the relative risk by 60% (0.4, 95% CI 0.3 to 0.5). Occupational category, job experience, and safety training were found to alter several of these effects.

Conclusion:The results suggest the importance of these transient, potentially modifiable factors in the aetiology of acute hand injury at work. Attempts to modify these exposures by various strategies may reduce the incidence of acute hand injury at work.
Long term effects of exposure to automobile exhaust on the pulmonary function of female adults in Tokyo, Japan
Authors: Sekine K , Shima M , Nitta Y , Adachi M
Published: March 2004

Aims:To investigate the chronic effects of air pollution caused mainly by automobiles in healthy adult females.

Methods:Respiratory symptoms were investigated in 5682 adult females who had lived in the Tokyo metropolitan area for three years or more in 1987; 733 of them were subjected to pulmonary function tests over eight years from 1987 to 1994. The subjects were divided into three groups by the level of air pollution they were exposed to during the study period. The concentrations of nitrogen dioxide and suspended particulate matter were the highest in group 1, and the lowest in group 3.

Results:The prevalence rates of respiratory symptoms in group 1 were higher than those in groups 2 and 3, except for wheezing. Multiple logistic regression analysis showed significant differences in persistent phlegm and breathlessness. The subjects selected for the analysis of pulmonary function were 94, 210, and 102 females in groups 1, 2, and 3, respectively. The annual mean change of FEV1in group 1 was the largest (−0.020 l/y), followed by that in group 2 (−0.015 l/y), and that in group 3 (−0.009 l/y). Testing for trends showed a significant larger decrease of FEV1with the increase in the level of air pollution.

Conclusions:The subjects living in areas with high levels of air pollution showed higher prevalence rates of respiratory symptoms and a larger decrease of FEV1compared with those living in areas with low levels of air pollution. Since the traffic density is larger in areas with high air pollution, the differences among the groups may reflect the effect of air pollution attributable to particulate matter found in automobile exhaust.
Pre-employment urine drug testing of hospital employees: future questions and review of current literature: Table 1
Authors: Levine M R , Rennie W P
Published: March 2004

Background:Patient safety and optimisation of worker performance are high current priorities. Arguments over employee drug testing have been debated over the past two decades.

Aims:To review prior information to reveal how current principles and practices regarding pre-employment drug testing of health care workers evolved, and to explore pressing current and future issues.

Methods:A literature search of Medline from 1980 to 1999 was performed. This yielded seven citations that reported results of pre-employment drug testing of health care workers, which we critically reviewed.

Results:The process by which a rational testing process was developed for pre-employment urine drug screening in the health care field is illustrated. Also depicted are some important principles, inequities, and shortcomings of the system. The range of positive tests was wide, from 0.25% to 12%. Testing was not always applied uniformly to all health care workers. It became apparent that positive tests also require medical review to determine if they were truly due to illicit substance use.

Conclusions:Although pre-employment drug testing programmes in the health care industry have been firmly in place for many years, it is unclear whether such strategies have achieved their stated purposes. The next step is to study whether such programmes are effective at accomplishing specific goals, such as decreasing absenteeism, turnover, accidents, and medical errors, in order to justify continuing pre-employment testing versus changing to an alternative testing strategy.
The effectiveness of ergonomic interventions on return-to-work after low back pain; a prospective two year cohort study in six countries on low back pain patients sicklisted for 3–4 months
Authors: Anema J R , Cuelenaere B , van der Beek A J , Knol D L , de Vet H C W , van Mechelen W
Published: March 2004

Aims:To study occurrence and effectiveness of ergonomic interventions on return-to-work applied for workers with low back pain (LBP).

Methods:A multinational cohort of 1631 workers fully sicklisted 3–4 months due to LBP (ICD-9 codes 721, 722, 724) was recruited from sickness benefit claimants databases in Denmark, Germany, Israel, Sweden, the Netherlands, and the United States. Medical, ergonomic, and other interventions, working status, and return-to-work were measured using questionnaires and interviews at three months, one and two years after the start of sickleave. Main outcome measure was time to return-to-work. Cox’s proportional hazards model was used to calculate hazard ratios regarding the time to return-to-work, adjusted for prognostic factors.

Results:Ergonomic interventions varied considerably in occurrence between the national cohorts: 23.4% (mean) of the participants reported adaptation of the workplace, ranging from 15.0% to 30.5%. Adaptation of job tasks and adaptation of working hours was applied for 44.8% (range 41.0–59.2%) and 46.0% (range 19.9–62.9%) of the participants, respectively. Adaptation of the workplace was effective on return-to-work rate with an adjusted hazard ratio (HR) of 1.47 (95% CI 1.25 to 1.72; p < 0.0001). Adaptation of job tasks and adaptation of working hours were effective on return-to-work after a period of more than 200 days of sickleave with an adjusted HR of 1.78 (95% CI 1.42 to 2.23; p < 0.0001) and 1.41 (95% CI 1.13 to 1.76; p = 0.002), respectively.

Conclusions:Results suggest that ergonomic interventions are effective on return-to-work of workers long term sicklisted due to LBP.
Building camps and work related injuries
Authors: Tüchsen F , Hannerz H
Published: March 2004

Aims:To focus on one possible predictor of reported work related injuries—the role of living in building-site camps versus daily commuting from home to construction sites.

Methods:A cohort of construction workers was collected, based on personnel files from contractors involved in the building of the Great Belt Bridge. The files included information on employment periods and whether or not the employees lived in building-site camps. The cohort was followed up for injuries reported to the National Work Environment Authority.

Results:Construction workers living in camps reported 217 accidents, of which 24 were serious or fatal. Among those not living in camps we found 262 accidents, of which 29 were serious or fatal. The relative risk for all accidents for camp versus non-camp was 0.84 (95% CI 0.69 to 1.00). The respective figure for serious or fatal accidents was RR = 0.85 (95% CI 0.47 to 1.52).

Conclusion:Results suggest that high accident rates at large construction sites may be reduced, if commuting is replaced by living on-site.
Biological monitoring of kidney function among workers occupationally exposed to trichloroethylene
Authors: Green T , Dow J , Ong C N , Ng V , Ong H Y , Zhuang Z X , Yang X F , Bloemen L
Published: March 2004

Aims:To investigate the nephrotoxic potential of trichloroethylene in a currently exposed population using sensitive urinary markers of kidney toxicity.

Methods:Renal dysfunction was monitored in a cross-sectional study of 70 workers currently exposed to trichloroethylene. An age and sex matched control population of 54 individuals was drawn from hospital and administrative staff.

Results:The mean exposure to trichloroethylene, estimated from urinary trichloroacetic acid concentrations, was 32 ppm (range 0.5–252 ppm) with an average duration of exposure of 4.1 years (range 1–20 years). Significant differences between the exposed and control populations were found for nephrotoxicity markers N-acetylglucosaminidase (NAG) and albumin, and for the mode of action marker, formic acid. However, neither NAG nor albumin showed a significant correlation with either the magnitude or duration of exposure to trichloroethylene. There was a significant correlation between urinary formic acid and trichloroacetic acid concentrations. Within the exposed population there were dose dependent increases in urinary methylmalonic acid concentrations and urinary glutathione S-transferase α activity. Although still within the control range, these changes were clearly dose dependent and consistent with one of the proposed mechanisms of trichloroethylene induced kidney toxicity.

Conclusion:Although there was no evidence of kidney toxicity within the population studied, the results suggest that kidney damage could occur at exposure concentrations higher (>250 ppm) than those encountered in this study.
Mortality patterns among residents in Louisiana’s industrial corridor, USA, 1970–99
Authors: Tsai S P , Cardarelli K M , Wendt J K , Fraser A E
Published: March 2004

Background:Because of the high concentration of oil refining and petrochemical facilities, the industrial area of the lower Mississippi River of South Louisiana has been termed the Industrial Corridor and has frequently been referred to as the “Cancer Corridor”.

Aims:To quantitatively assess the “Cancer Corridor” controversy based on mortality data available in the public domain, and to identify potential contributing factors to the observed differences in mortality.

Methods:Age adjusted mortality rates were calculated for white and non-white males and females in the Industrial Corridor, Louisiana, and the United States for the time periods 1970–79, 1980–89, and 1990–99.

Results:All-cause mortality and all cancer combined for white males in the Industrial Corridor were significantly lower than the corresponding Louisiana population while Louisiana had significantly higher rates than the US population for all three time periods. Cancer of the lung was consistently higher in the Industrial Corridor region relative to national rates but lower than or similar to Louisiana. Non-respiratory disease and cerebrovascular disease mortality for white males in the Industrial Corridor were consistently lower than either Louisiana or the USA. However, mortality due to diabetes and heart disease, particularly during the 1990s, was significantly higher in the Industrial Corridor and Louisiana when compared to the USA. Similar mortality patterns were observed for white females. The mortality for non-white males and females in the Industrial Corridor was generally similar to the corresponding populations in Louisiana. There were no consistent patterns for all cancer mortality combined. Stomach cancer was increased among non-whites in both the Industrial Corridor and Louisiana when compared to the corresponding US data. Mortality from diabetes and heart disease among non-whites was significantly higher in the Industrial Corridor and Louisiana than in the USA.

Conclusions:Mortality rates in the Industrial Corridor area were generally similar to or lower than the State of Louisiana, which were increased compared to the United States. Contrary to prior public perceptions, mortality due to cancer in the Industrial Corridor does not exceed that for the State of Louisiana.
Malignant pleural and peritoneal mesotheliomas in former miners and millers of crocidolite at Wittenoom, Western Australia
Authors: Berry G , de Klerk N H , Reid A , Ambrosini G L , Fritschi L , Olsen N J , Merler E , Musk A W
Published: March 2004

Aims:To report the number of malignant pleural and peritoneal mesotheliomas that have occurred in former Wittenoom crocidolite workers to the end of 2000, and to compare this with earlier predictions.

Methods:A group of 6493 men and 415 women who had worked at the former Wittenoom crocidolite mine and mill at some time between 1943 and 1966 have been followed up throughout Australia and Italy to the end of 2000.

Results:The cumulative number of mesotheliomas up to 2000 was 235 in men (202 pleural, 33 peritoneal) and seven (all pleural) in women. There had been 231 deaths with mesothelioma (9% of known deaths).

Conclusions:The number of deaths in men with mesothelioma between 1987 and 2000 was at the low end of the predictions made earlier based on the number of cases to 1986. If this trend continues, it is predicted that about another 110 deaths with mesothelioma will occur in men by 2020.
Biomarkers of exposure to polycyclic aromatic hydrocarbons from environmental air pollution
Authors: Castaño-Vinyals G , D’Errico A , Malats N , Kogevinas M
Published: March 2004

Metabolites of pyrene and DNA adducts have been used as biomarkers of high level exposure to polycyclic aromatic hydrocarbons (PAHs). A systematic review was performed to evaluate whether these biomarkers are also valid markers of low level environmental exposure to PAHs. Thirty five studies were identified with more than 10 subjects that evaluated environmental air pollution to PAHs in relation to metabolites of PAHs, mainly hydroxypyrene (1-OHP), PAH-DNA adducts, or protein adducts. PAH metabolites and, to a less extent, PAH-DNA adducts correlated well at the group level with exposure to B(a)P even at low levels of air pollution. The use of these biomarkers should be more widely implemented in combination with more traditional techniques for the assessment of general population exposure to PAHs from ambient air pollution.
Paternal exposure to agricultural pesticides and cause specific fetal death
Authors: Regidor E , Ronda E , García A M , Domínguez V
Published: March 2004

Aims:To study the association between fetal death and paternal agricultural occupation in areas and time periods with different levels of use of agricultural pesticides.

Methods:A total of 1 473 146 stillbirths and births occurring in Spain between 1995 and 1999 were analysed.

Results:The offspring of agricultural workers had the highest risk of fetal death from congenital anomalies in the southern and eastern area (where pesticide use is greatest) and the lowest risk in the rest of Spain. In both areas the offspring of agricultural workers had a similar excess risk of fetal death from the remaining causes of death. The relative risk of fetal death from congenital anomalies in infants conceived between April and September (the months of greater use of pesticides) in the southern and eastern area was 0.90 in manual workers and 1.62 in agricultural workers, compared to non-manual workers; in individuals who were conceived during the rest of the year, the relative risk was 0.87 and 0.85, respectively. In both periods the offspring of agricultural workers had an excess risk of fetal death from the remaining causes of death.

Conclusions:Paternal agricultural work in the areas where pesticides are massively used increases the risk of fetal death from congenital anomalies. The risk is also increased for fetuses conceived during the time periods of maximum use of pesticides The higher risk of fetal death from the remaining causes of death in the offspring of agricultural workers seems unrelated to pesticide exposure.
Cigarette smoking, occupational exposure to noise, and self reported hearing difficulties: Table 1
Authors: Palmer K T , Griffin M J , Syddall H E , Coggon D
Published: March 2004

Aims:To explore the interaction of smoking and occupational exposure to noise as risk factors for hearing difficulty in the general population.

Methods:A questionnaire was mailed to 21 201 adults of working age, selected at random from the age-sex registers of 34 British general practices, and to 993 members of the armed services, randomly selected from pay records. Questions were asked about smoking habits, years spent in a noisy occupation, difficulty in hearing conversation, and wearing of a hearing aid. Associations of hearing difficulty with smoking habit were examined by logistic regression and compared across strata of noise exposure, with adjustment for potential confounders.

Results:Around half of the respondents had ever smoked, and half of these still smoked. Among 10 418 who provided details on hearing, 348 were classed as having moderate and 311 as having severe hearing difficulty. Risk of hearing difficulty was 3–5-fold higher in those employed for >5 years in noisy work compared with those never employed in a noisy job. Within strata of noise exposure (including those who had never worked in a noisy job), ex- and current smokers had a higher risk of hearing difficulty than lifetime non-smokers. The additional risks were small compared with those of long term noise exposure, and the combination of effects was more consistent with an additive than a multiplicative interaction.

Conclusions:Smoking may adversely affect hearing, and workers should be encouraged to refrain from both smoking and exposure to noise. However, the extra risk to hearing incurred by smoking in high ambient noise levels is small relative to that from the noise itself, which should be the main target for preventive measures.
TIME AND ENERGY OPTIMAL LIST RANKING ALGORITHMS ON THE k-CHANNEL BROADCAST COMMUNICATION MODEL WITH NO COLLISION DETECTION
Authors: NAKANO KOJI
Published: March 2004

A Broadcast Communication Model (BCM, for short) is a distributed system with no central arbiter populated by n processing units referred to as stations. The stations can communicate by broadcasting/receiving a data packet to one of k distinct communication channels. We assume that the stations run on batteries and expend power while broadcasting/receiving a data packet. Thus, the most important measure to evaluate algorithms on the BCM is the number of awake time slots, in which a station is broadcasting/receiving a data packet. The main contribution of this paper is to present time and energy optimal list ranking algorithms on the BCM. We first show that the rank of every node in an n-node linked list can be determined in O(n) time slots with no station being awake for more than O(1) time slots on the single-channel n-station BCM with no collision detection. We then extend this algorithm to run on the k-channel BCM. For any small fixed ∊>0, our list ranking algorithm runs in [Formula: see text] time slots with no station being awake for more than O(1) time slots, provided that k≤n1-∊. Clearly, [Formula: see text] time is necessary to solve the list ranking problem for an n-node linked list on the k-channel BCM. Therefore, our list ranking algorithm on the k-channel BCM is time and energy optimal.
ON THE k-TRUCK SCHEDULING PROBLEM
Authors: MA WEIMIN , XU YINFENG , YOU JANE , LIU JAMES , WANG KANLIANG
Published: March 2004

In this paper, some results concerning the k-truck problem are produced. Firstly, the algorithms and their complexity concerning the off-line k-truck problem are discussed. Following that, a lower bound of competitive ratio (1+θ)·k/(θ·k+2) for the on-line k-truck problem is given, where θ is the ratio of cost of the loaded truck and the empty truck on the same distance, and a relevant lower bound for the on-line k-taxi problem followed naturally. Thirdly, based on the Position Maintaining Strategy (PMS), some new results which are slightly better than those of [11] for general cases are obtained. For example, a c-competitive or (c/θ+1/θ+1)-competitive algorithm for the on-line k-truck problem depending on the value of θ, where c is the competitive ratio of some algorithm to a relevant k-server problem, is developed. The Partial-Greedy Algorithm (PG) is used as well to solve this problem on a line with n nodes and is proved to be a (1+(n-k)/θ)-competitive algorithm for this case. Finally, the concepts of the on-line k-truck problem are extended to obtain a new variant: Deeper On-line k-Truck Problem (DTP). We claim that results of PMS for the STP (Standard Truck Problem) hold for the DTP.
MULTICASTING AND BROADCASTING IN UNDIRECTED WDM NETWORKS AND QoS EXTENTIONS OF MULTICASTING
Authors: XU YINLONG , LIN LI , CHEN GUOLIANG , WAN YINGYU , GUO WEIJUN
Published: March 2004

This paper addresses multicasting and broadcasting in undirected WDM networks and QoS extensions of multicasting. It is given an undirected network G=(V, E), with Λ is the set of the available wavelengths in G, and associated with each edge, there is a subset of wavelengths on it. For a multicast request r=(s, D) with a source s and a set D of destinations, it is to find a tree rooted at s including all nodes in D such that the cost of the tree is minimized in terms of the cost of wavelength conversion at nodes and the cost of using wavelength on edges. This paper proves that multicasting in this model of networks is NP-Hard and cannot be approximated within a constant factor, unless P=NP. Furthermore, an auxiliary graph is constructed for the original WDM network, the multicasting is reduced to a group Steiner tree problem on the auxiliary graph and an approximate algorithm based on the group Steiner tree algorithm proposed by M. Charikar et al. with performance ratio of O( log 2(nk) log log (nk) log p) is provided, where k=|Λ| and p=|D∪{s}|. At last, some QoS extensions of multicasting are discussed.
SINGLE-PUSHOUT TRANSFORMATION OF TOTAL ALGEBRAS
Authors: ALBERICH RICARDO , LLABRÉS MERCÈ , ROSSELLÓ FRANCESC
Published: March 2004

We characterize the pairs of partial homomorphisms of total Σ-algebras that have a pushout in the corresponding category, for an arbitrary signature Σ. This characterization provides the application condition for the single-pushout approach to the transformation of total algebras.
MODELING AND SYNTHESIS OF COMPLEX SYMMETRICAL IMAGES
Authors: HRYTSYK V. V. , BEREZSKA K. M. , BEREZSKY O. M.
Published: March 2004

We propose a method of description and modeling of complex symmetrical images, which can be used for the synthesis of ornamental patterns. Our approach allows considerable memory reduction for storing symmetrical images and considerable time reduction for their synthesis. Our algorithms for ornamental patterns synthesis suggest the design of a special purpose ornamental patterns editor which can store and synthesize symmetrical images.
TRACKING MULTIPLE MOVING OBJECTS USING A LEVEL-SET METHOD
Authors: CHANG CHIA-JUNG , HSIEH JUN-WEI , CHEN YUNG-SHENG , HU WEN-FONG
Published: March 2004

This paper presents a novel approach to track multiple moving objects using the level-set method. The proposed method can track different objects no matter if they are rigid, nonrigid, merged, split, with shadows, or without shadows. At the first stage, the paper proposes an edge-based camera compensation technique for dealing with the problem of object tracking when the background is not static. Then, after camera compensation, different moving pixels can be easily extracted through a subtraction technique. Thus, a speed function with three ingredients, i.e. pixel motions, object variances and background variances, can be accordingly defined for guiding the process of object boundary detection. According to the defined speed function, different object boundaries can be efficiently detected and tracked by a curve evolution technique, i.e. the level-set-based method. Once desired objects have been extracted, in order to further understand the video content, this paper takes advantage of a relation table to identify and observe different behaviors of tracked objects. However, the above analysis sometimes fails due to the existence of shadows. To avoid this problem, this paper adopts a technique of Gaussian shadow modeling to remove all unwanted shadows. Experimental results show that the proposed method is much more robust and powerful than other traditional methods.
CLASSIFICATION OF MULTITEMPORAL REMOTE-SENSING IMAGES BY A FUZZY FUSION OF SPECTRAL AND SPATIO-TEMPORAL CONTEXTUAL INFORMATION
Authors: MELGANI FARID
Published: March 2004

A fuzzy-logic approach to the classification of multitemporal, multisensor remote-sensing images is proposed. The approach is based on a fuzzy fusion of three basic sources of information: spectral, spatial and temporal contextual information sources. It aims at improving the accuracy over that of single-time noncontextual classification. Single-time class posterior probabilities, which are used to represent spectral information, are estimated by Multilayer Perceptron neural networks trained for each single-time image, thus making the approach applicable to multisensor data. Both the spatial and temporal kinds of contextual information are derived from the single-time classification maps obtained by the neural networks. The expert's knowledge of possible transitions between classes at two different times is exploited to extract temporal contextual information. The three kinds of information are then fuzzified in order to apply a fuzzy reasoning rule for their fusion. Fuzzy reasoning is based on the "MAX" fuzzy operator and on information about class prior probabilities. Finally, the class with the largest fuzzy output value is selected for each pixel in order to provide the final classification map. Experimental results on a multitemporal data set consisting of two multisensor (Landsat TM and ERS-1 SAR) images are reported. The accuracy of the proposed fuzzy spatio-temporal contextual classifier is compared with those obtained by the Multilayer Perceptron neural networks and a reference classification approach based on Markov Random Fields (MRFs). Results show the benefit of adding spatio-temporal contextual information to the classification scheme, and suggest that the proposed approach represents an interesting alternative to the MRF-based approach, in particular, in terms of simplicity.
OPTIMIZING FEEDFORWARD NEURAL NETWORKS FOR CONTROL CHART PATTERN RECOGNITION THROUGH GENETIC ALGORITHMS
Authors: GUH RUEY-SHIANG
Published: March 2004

Pattern recognition is an important issue in statistical process control (SPC) because unnatural patterns exhibited by control charts can be associated with specific assignable causes adversely affecting the process. Artificial neural networks have been widely investigated as an effective approach to control chart pattern (CCP) recognition in recent years. However, an overwhelming majority of these applications has used trial-and-error experiments to determine the network architecture and training parameters, which are crucial to the performance of the network. In this paper, the genetic algorithm (GA) is used to evolve the configuration and the training parameter set of the neural network to solve the online CCP recognition problem. Numerical results are provided that indicate that the proposed GA can evolve neural network architecture while simultaneously determining training parameters to maximize efficiently the performance of the online CCP recognizers. Because the population size is a major parameter of GA processing speed, an investigation was also conducted to identify the effects of the population size on the performance of the proposed GA. This research further confirms the feasibility of using GA to evolve neural networks. Although a back-propagation-based CCP recognizer is the particular application presented here, the proposed GA methodology can be applied to neural networks in general.
DETECTION OF MOVING SMALL TARGETS IN INFRARED IMAGE SEQUENCES CONTAINING CLOUD CLUTTER
Authors: WU WEI , PENG JIAXIONG
Published: March 2004

Detecting and tracking dim moving small targets in infrared image sequences containing cloud clutter is an important area of research. The paper proposes a novel algorithm for the dim moving small target detection in cloudy background. The algorithm consists of three courses. The first course consists of the image spatial filtering and the sequence temporal filtering, it can be realized by two parallel calculative parts. The second course is the fusion and the segmentation processing. The last course is the targets acquiring and tracking, it can be achieved by the Kalman tracker. The results of our experiment prove that the algorithm is very effective.
GENERALIZED SPECTROFACE FOR FACE RECOGNITION
Authors: LAI JIAN-HUANG , YUEN PONG C. , DENG DONG-GAO
Published: March 2004

Spectroface is a face representation method using wavelet transform and Fourier transform and has been proved to be invariant to translation, on-the-plane rotation and scale. Two types of spectrofaces, namely first order and second order spectrofaces, have been proposed and successfully applied for face recognition. This paper reports a generalized spectroface, in which, we prove that any continuous and compact supported low-pass filters can be used to replace the wavelet transform. This feature provides a high flexibility of the spectroface representation. It is also proved that the generalized spectroface is translation invariant. A simple but effective feature selection algorithm is also proposed for the generalized spectroface in which the recognition is further increased. Three standard databases from Yale University, Olivette Research Laboratory and MIT, are used to evaluate the proposed method. The recognition accuracy is as high as 99.29%. If we consider the top three matches, the accuracy increases to 99.64%.