Automatic mura detection based on thresholding the fused normalized first and second derivatives in four directions

Abstract— The size of flat‐panel liquid‐crystal displays is getting larger; as a result, it is becoming harder to inspect for defects and may require a human visual inspector to judge the severity of the defects on the final product. Recently, mura phenomenon, which is defined as a visual blemish with non‐uniform shapes and boundaries, is becoming a serious unpleasant effect which needs to be detected and inspected in orderto standardize the LCD's quality. Hence, an automation process based on machine vision has proven to be a good choice to facilitate and stabilize the process. An effective general algorithm for detecting different types of mura defects with various contrast, shape, and direction, based on the fusion of the normalized magnitude of first‐ and second‐order derivative responses in four directions, is proposed. The experiments applied on various types of pseudo‐mura with different shapes show an efficient detection rate of more than 90%.     

Comparison of different treatment alternatives for removal of pesticide from water solution

BACKGROUND: Removal of recalcitrant chemicals is an essential step in conventional wastewater treatment plants. Among these, pesticides are of great environmental concern. Different treatment options were compared in this work: the combination of advanced oxidation processes (AOPs) with biological treatment, an aerobic process and anaerobic biological treatments. The role of chemical processes in improving solution biodegradability was verified. Oxidation by‐products were identified and biological process kinetics are reported. The performance of biological processes and their kinetics were studied. RESULTS: Chemical oxidation increased the solution biodegradability index to 0.25. Oxidation by‐products were identified as maleic acid, phenol and a mixture of catechol, resorcinol and hydroquinone. The combined processes resulted in 98% organic matter removal. Pesticide degradation followed pseudo‐first‐order kinetics with a rate constant in the range 0.5–1.2 L g^?1TVSS h^?1. An anaerobic process was found to be an attractive option with 92% removal efficiency. The aerobic process had a long adaptation time (>200 days), 80% removal efficiency and an average pseudo‐first‐order rate constant of 0.18 L g^?1TVSS h^?1. CONCLUSION: Comparison of the investigated processes favoured the use of combined AOPs and biological and/or aerobic biological treatment due to its practical operating conditions. Copyright © 2009 Society of Chemical Industry     

Optimizing the utilization of multiple labor shifts in construction projects

Evening and night shifts are often used in construction projects to accelerate schedules despite their negative impacts on construction cost and productivity. In order to minimize these negative impacts, this paper presents a multi-objective optimization model for scheduling multiple labor shifts in construction projects. The optimization model incorporates (1) an initialization module that initializes the scheduling optimization computations; (2) a scheduling module that develops practical multiple shift schedules and evaluates the impacts of decision variables on project performance; and (3) a multi-objective genetic algorithm module that searches for and identifies optimal/near optimal tradeoffs among minimizing project duration, reducing cost, and minimizing labor utilization in evening and night shifts. An application example is analyzed to illustrate the use of the model and demonstrate its capabilities in optimizing the planning and scheduling of multiple shifts in construction projects while complying with all job logic and labor availability constraints.     

CFRP-Strengthened and Corroded RC Beams under Monotonic and Fatigue Loads

An experimental program has been carried out to investigate the structural behavior of RC beams strengthened by carbon-fiber–reinforced polymer (CFRP) sheets and exposed to a corrosive environment. A total of eight specimens (120 × 175 × 2,000 mm) were tested. Six specimens were CFRP strengthened and corroded, one specimen was unstrengthened and corroded, and one specimen was neither strengthened nor corroded. Two different strengthening schemes were applied: (1) wrapping the specimen with CFRP sheets; and (2) both specimen wrapping and flexural strengthening. Three specimens were tested under monotonic loading and five specimens were tested in fatigue. The results showed that the use of CFRP sheets for strengthening RC beams that are experiencing steel reinforcement corrosion is an efficient technique that can maintain the structural integrity and enhance the structural behavior of such beams. The ultimate monotonic strength of the CFRP strengthened-corroded specimens increased to a level between 37 and 87% above the predicted strength of a similar unstrengthened-uncorroded (virgin) specimen. The fatigue life of the CFRP strengthened-corroded specimens was increased within a range of 2.5–6.0 times that of a similar unstrengthened-corroded specimen but was lower than that of the uncorroded (virgin) specimen.     

Impact of Rainfall on the Productivity of Highway Construction

Heavy rainfall often leads to complete suspension of highway construction due to saturated and unworkable soil conditions. Therefore, quantifying the impact of rainfall on the productivity of highway construction is essential in preparing realistic schedules and cost estimates for the preconstruction stage and in analyzing weather-related claims for the postconstruction stage. This paper presents a decision support system for quantifying the impact of rainfall on productivity and duration of common highway construction operations, namely: earthmoving, construction of base courses, construction of drainage layers, and paving operations. The system incorporates a knowledgebase and a database. The knowledgebase includes if∕then type rules, acquired from experts in highway construction operations, and the database contains hourly records of weather parameters from the closest weather station to the construction site. The system, named WEATHER, is a software system that provides user-friendly interface, including menus, dialog boxes, and graphical capabilities to facilitate data input and output.     

State-of-the-Art in Design of Curved Box-Girder Bridges

The objective of this paper is to provide highlights of the most important references related to the development of current guide specifications for the design of straight and curved box-girder bridges. Subjects discussed in this review include (1) different box-girder bridge configurations; (2) construction issues; (3) deck design; (4) load distribution; (5) deflection and camber; (6) cross-bracing requirements; (7) end diaphragms; (8) thermal effects; (9) vibration characteristics; (10) impact factors; (11) seismic response; (12) ultimate load-carrying capacity; (13) buckling of individual components forming the box cross section; (14) fatigue; and (15) curvature limitations provided by the codes for treating a curved bridge as a straight one. The literature survey presented herein encompasses (1) the construction phase; (2) load distribution; (3) dynamic response; and (4) ultimate load response of box-girder bridges.     

User participation in the requirements engineering process: An empirical study

In the development of information systems, user participation in the requirements engineering (RE) process is hypothesised to be necessary for RE success. In this paper we develop a theoretical model which predicts that the interaction between user participation in the RE process and uncertainty has an impact on RE success. This theory is empirically tested using survey data. We develop instruments to measure user participation and uncertainty. An existing instrument for measuring RE success was used. This instrument covers two dimensions of RE success: (a) the quality of RE service, and (b) the quality of RE products. The results, indicate that as uncertainty increases, greater user participation alleviates the negative influence of uncertainty on the quality of RE service, and that as uncertainty decreases, the beneficial effects on the quality of RE service of increasing user participation diminish. Furthermore, we did not find that the interaction between user participation and uncertainty had an impact on the quality of RE products. Based on these results, we make recommendations for managing user participation in the RE process, and provide directions for future research.This work has been supported, in part, by the IT Macroscope Project and NSERC Canada.