Luh-Maan Chang

DIGITAL IMAGE PROCESSING METHODS FOR ASSESSING BRIDGE PAINTING RUST DEFECTS AND THEIR LIMITATIONS

Accurate and objective rust defect assessment is required to maintain a good -quality steel bridge painting surfaces and make a decision whether a bridge shall completely or partially be repainted. For more objective rust defect recognition, digital image recognition methods have been developed for the past few years and they are expected to replace or complement conventional painting inspection methods. Efficient image processing methods are also essential for the successful implementation of steel bridge coating warranty contracting where the owner, usually a state agency, and the contractor inspect steel bridge coa ting conditions regularly and decide whether additional maintenance actions are needed based on the processed data. Previously developed image recognition methods for painting rust defect assessment can be summarized as two: the NFRA (Neuro-Fuzzy Recognition Approach) method and the SKMA (Simplified K-Means Algorithm) method. The NFRA method uses artificial intelligence techniques to separate rust pixels from background pixels. The SKMA method segments object pixels and background pixels in a digitized ima ge using a statistical method, called the K-means algorithm. Even if both methods pass through different processing procedures, one common thing is that they first convert original color images to grayscale images and further process the grayscale images. This article presents the application of previously developed image processing methods for painting rust defect evaluation s and discusses their limitations under several specific environmental conditions which are often encountered while acquiring digital images.

QUANTIFYING IMPACTS OF CONSTRUCTION PROJECT CHARACTERISTICS ON ENGINEERING PERFORMANCE: A FUZZY NEURAL NETWORK APPROACH

Performance of the different parties participating in a construction project, particularly engineering professionals, plays an important role in its successful or unsuccessful implementation. This paper presents a study conducted to investigate how project characteristics impact engineering performance in measurable terms. A comprehensive approach that benefits from the capabilities of fuzzy neural networks (FNNs), utility functions and the analytical hierarchy process (AHP) is specifically employed for such purpose. In this context, utility functions and AHP are integrated together to develop a n instrument for measuring engineering performance, while FNNs are used to develop a connectionist structure relating engineering performance to its influential project characteristics. For practicality, the study is implemented in the industrial construct ion sector. The paper begins with a discussion of the topic of engineering performance and the conventional methods for its measurement in the construction industry. Following is an overview of the adopted approach and the analytical capabilities it has. A fterwards, the paper presents the details of the system used for quantifying the sought impacts in the industrial construction sector, including, the basic architecture of the system and the data sets used in its development. Applying the developed system in quantifying the impact of example project characteristics is also illustrated. Lastly, conclusions of the study are drawn.

EVALUATION AND POLICY FOR BRIDGE DECK EXPANSION JOINTS

This report is an overview of the research that was performed for the Indiana Department of Transportation (INDOT) concerning the performance of bridge deck expansion joints. The purpose of the research is to evaluate several types of joints currently in use and also provide the evaluation criteria for rating the joint condition. The types of joints investigated are Compression Seal (B.S.) joint, Strip Seal (S.S.) joint, Integral Abutment Jointless (I.A.) joint, Poured Silicone (XJS) joint, and Polymer Modified Asphalt (LDI and PaveTech) joint. The research was performed by two questionnaire surveys, Roadway Management data analysis, expert interviews, and site assessment. The problems and their causes, the merits, the potential improvements, and the estimated lives of these types of joints were identified from the questionnaire surveys. The results showed that the S.S., B.S., and I.A. joints are rated as the top three for their longer estimated lives as well as other attributes. The results of the factor and logistic regression analyses of the INDOT Roadway Management data indicate that the performances of the S.S., B.S., and I.A. joints are rated first, second, and third respectively, based on deterioration rates under identical conditions of traffic loading, settlement, and age. Other types of joints could not be analyzed due to insufficient data. The investigation of the practices of surrounding states revealed that each state has its own experiences in using and maintaining the joints. There are no uniform drawings, specifications, and maintenance strategies among the investigated states. Finally, the research provides pilot evaluation schemes for inspecting joints. Based on the findings of this research, an implementation policy has been designed to ensure the longer service life of expansion joints.

Object-Based Learning Method in Engineering

Numerous researchers have developed learning methods that can be used in different situations and conditions, which has led multiple theories and related applications. Traditionally, most learning occurs in a formal classroom setting; however, because of technology there has been considerable research on computer-based learning technologies that deliver anytime, anywhere, and at a lower cost. As Industry moves from traditional craft-base operations to more sophisticated technology-oriented processes, needs for sustaining education have increased correspondingly. Among the computer-based technologies being explored is object-based learning method, which is believed to offer new opportunities for learning in academics and industry. Object-based learning is an instructional strategy that is based on the idea that people can learn from an object by exploring the object and its context. Typically, object-based learning is in the form of bite-sized components that could be used in combination with other objects to provide a variety of learning, customized to a learner’s needs, levels, and goals and then rearranged for another purpose and different end-users. This paper describes an Object Based Learning Model (OBLM) that is being developed at Purdue University. The OBLM is an on-line tool that can be used in either Industry or Academia. It consists of a digital warehouse that stores the on-line content in a structure used by course developers to expedite the development of online content. On-line content can utilize the standard forms of content (e.g., document files, PowerPoint slides, movie files, images, etc.). Interfaces for the course developer/instructor and the student will use the object based approach. The proposed object-based learning method is expected to offer many potential advantages particularly in the engineering disciplines. It can provide a significantly better learning environment for engineering topics in terms of flexibility, portability, and distributive learning.

XML Application in AEC Industry

The exchange and reuse of the information have become a much more critical issue for the success of the project management in the Architecture, Engineering and Construction (AEC) industry. The appearance of Extensible Markup Language (XML) provides a potentially well-adopted solution to alleviate the pain of data exchange. Based on XML, this research proposes an XML-based Distributed Construction Estimating System (XDCES) to reduce the redundancy and overload of cost estimating information exchange. Thus, information can be inputted once and reused where and when necessary. In this way, although, the focus of XDCES is on the estimating task, its conclusions are generally applicable to other forms of information exchange. In addition, this research surveys several existing XML applications in the AEC industry and proposes a framework for the ongoing aecXML, a framework for using the XML standard for electronic communications in the AEC industry.

BOT Financing in Public Infrastructure Projects

Built-Operate-Transfer (BOT) is a new approach to the implementation of public infrastructure project. In this approach, the concession right is granted to the private sector to invest in the infrastructure and operate the system for a certain time period. Financial feasibility is the key to determine whether a BOT project is accepted. This paper compares the different focuses on the financial feasibility analysis applied in the fully government funded project and the BOT project. The practical implications &these differences are discussed.

Construction Quality Control Through Pen-Based Computers

This paper describes research results and the experience gained by applying pencomputers to the area of construction quality. A pen-based computer system has been developed to include the functions of signature, error detection, drawing capability, form navigation, user instruction, and decision making. The system eliminates the required effort to convert the inspection data from paper forms to computers input. Moreover, it contains statistical algorithms to automatically facilitate either accepting or rejecting the quality of a finished construction product. A pen-based computer provides many benefits. This paper will begin with a brief review of the pen-based computer technology followed by detailed design of the pen-based computer system for quality inspection of steel bridge painting. Finally, conclusions and recommendations will be provided.