Bonsang Koo

A suggested color scheme for reducing perception-related accidents on construction work sites.

Changes in workforce demographics have led to the need for more sophisticated approaches to addressing the safety requirements of the construction industry. Despite extensive research in other industry domains, the construction industry has been passive in exploring the impact of a color scheme; perception-related accidents have been effectively diminished by its implementation. The research demonstrated that the use of appropriate color schemes could improve the actions and psychology of workers on site, thereby increasing their perceptions of potentially dangerous situations. As a preliminary study, the objects selected by rigorous analysis on accident reports were workwear, safety net, gondola, scaffolding, and safety passage. The colors modified on site for temporary facilities were adopted from existing theoretical and empirical research that suggests the use of certain colors and their combinations to improve visibility and conspicuity while minimizing work fatigue. The color schemes were also tested and confirmed through two workshops with workers and managers currently involved in actual projects. The impacts of color schemes suggested in this paper are summarized as follows. First, the color schemes improve the conspicuity of facilities with other on site components, enabling workers to quickly discern and orient themselves in their work environment. Secondly, the color schemes have been selected to minimize the visual work fatigue and monotony that can potentially increase accidents.

Which Strategies Are More Effective for International Contractors during Boom and Recession Periods

AbstractGiven the global financial crisis and other plummeting market conditions in 2008, the international construction market moved from boom to recession. Although this recession is expected to be completed soon, many international contractors still have difficulty deciding on the strategies that are more effective during volatile market conditions. Korean contractors have already experienced one recession in recent times, instigated by the Asian financial crisis in 1997, and two boom economies before and after this recession. To investigate more effective strategies used in the overseas construction market, this study evaluates 31 Korean contractors’ international performance over the different periods (boom, recession, and reboom) and analyses the effects of diversification, localization, strategic alliance, resources cost allocation, and financial soundness by using 14 key variables. The results showed that regional diversification had a profound effect on overcoming the recessionary periods. Locali...

Empirical Assessment of International Entry Strategy for Large Construction Companies

Although international construction market gradually takes a important position among the export industries, the previous studies about international construction entry strategy have just focussed on trend investigation or suggestion for revitalization. Moreover, in order to prepare the market uncertainty such as world financial crisis and to plan the long term strategy, specific strategy studies based on corporate level are required. Therefore, this study estimates the nine strategic index and four financial index of 31 companies that performed 1920 international projects from 1993 to 2007 and evaluate the performance as three periods by multi-regression analysis. Also, this study analyze dynamic correlation between these index and the performance considering times. this study verifies that market diversification, product diversification, localization and decrease of debt to asset ratio make a good effect on the international order as long term strategy and shows that collaborated entry with domestic corporations, alliance entry with host country`s company, alliance entry with third country`s company, portion of labor cost and portion of management expense differently make a influence on the performance as times. these results will be helpful for the construction companies to plan the international entry strategy reasonably and specifically.

Using Real Options to value the flexibility of Engineering Management decisions in Infrastructure Projects

Abstract: Determining on a particular construction method is typically decided in the initial phases of a project. However, changing conditions during actual construction may require a different method or technology to be employed. Providing an option for project managers to change construction provides flexibility that can increase value to the overall project. This research provides the ability to modify construction methods as a real option, which allows its value to be modeled. The research also formalizes a way to integrate a bi nomial lattice model with the Earned Value Method’s S -curve. The integrated model provides a decision support tool that planners can use to determine whether to exercise the option depending on the status metrics provided by EVM. Keywords: Real Options, Earned Value, Construction Methods, Risk Management I. I NTRODUCTION Construction projects have inherent risks that exist throughout the planning, design, construction and O&M phases of the project. In particular, risks during the construction phase of a project are difficult to predict beforehand, and thus project managers must be given the authority to deal with such risks flexibly. One way of dealing with construction risks is to change or modify the method of construction technology initially planned for a specific type of work. Allowing the project manager to change to a different method that is cheaper or faster provides ‘managerial flexibility’ and thus ensures that the project is within budget and on time. Enabling construction methods to be modified during the construction phase is in fact allowing project managers to delay the decision to choose a particular construction method in the upstream phases such as planning and design. That is, it provides project managers the option or the right to delay, postpone or switch a decision until more information is available to them. Such rights are referred to as ‘real options.’ Several research exist that have adopted real options theory to evaluate the value of deferred or switched decisions of construction projects, with a focus on PPP (public private partnership) projects. [4], [6], [7]. However, most of this research has been focused on delaying decisions until revenues have shown the need to expand the scope of the project. In this research, we focus specifically on the construction phase of the project, and how decisions can be made based on the current status of the project. More specifically, we focus on modeling the ‘right’ of delaying or switching the decision making of construction methods during the construction phase as a real option. We use the binomial tree method, a method of real option analysis, to value the option of delaying the decision of the specific construction method so that contractors have more ‘managerial flexibility’ with which they can react to uncertainty risks occurring the actual construction phase. Also we link the option valuation tree (OVT) with the outputs of the EVM. The option valuation tree provides when and what costs an option should be exercised, while EVM provide information as to the current status of the project. Thus, if a project has been delayed, a contractor may refer to the OVT to determine whether changing to a different construction method is a better strategy. The linking of the two models enables EVM to be better utilized as a decision support tool, as to a restrictive monitoring tool. II. L

A Constraint Ontology and Classification Mechanism for Automatic Inference of the Role and Status of Activities in CPM-based Schedules

The ability to re-sequence activities is a critical task for project planners for effective project control. When re-sequencing activities, planners need to determine the role and “status” of activities (i.e., whether activities can or cannot be delayed), which they infer based on the rationale between activity sequences. The current CPM framework only distinguishes activities with respect to their time-criticality and represents sequencing rationale using precedence relationships. Thus, CPM-based schedules make it difficult for planners to modify existing schedules to evaluate and generate sequencing alternatives. These limitations has been addressed by formalizing a constraint ontology and classification mechanism. The constraint ontology allows explicit representation of the rationale for activity sequences in CPM-based schedules, while the classification mechanism leverages the ontology to automate the inference of the role and status of activities. These formalizations were implemented in a prototype system called “Constraint-loaded CPM” (CLCPM). With this tool, users can keep track of the different types of rationale for activity sequencing logic, and discern which activities to delay to expedite milestone or bottleneck activities. Thus, the formalizations provide planners with the information they need to easily and quickly evaluate and generate sequencing alternatives.

Applying novelty detection to identify model element to IFC class misclassifications on architectural and infrastructure Building Information Models

Abstract Ensuring the correct mapping of model elements to Industry Foundation Classes (IFC) classes is fundamental for the seamless exchange of information between Building Information Modeling (BIM) applications, and thus achieve true interoperability. This research explored the possibility of employing novelty detection, a machine learning approach, as a way to detect potential misclassifications that occur during current ad hoc and manual mapping practices. By training the algorithm to learn the geometry of BIM elements for a given IFC class, outliers are detected automatically. A framework for leveraging multiple BIM models and training individual one-class SVM’s was formulated and tested on four IFC classes. Performance results demonstrate the classification models to be robust and unbiased. The algorithms developed thus can be leveraged to check the integrity of IFC data, a prerequisite for BIM-based quality control and code compliance.

Employing Outlier and Novelty Detection for Checking the Integrity of BIM to IFC Entity Associations

Although Industry Foundation Classes (IFC) provide standards for exchanging Building Information Modeling (BIM) data, authoring tools still require manual mapping between BIM entities and IFC classes. This leads to errors and omissions, which results in corrupted data exchanges that are unreliable and compromise the interoperability of BIM models. This research explored the use of two machine learning techniques for identifying anomalies, namely outlier and novelty detection to determine the integrity of IFC classes to BIM entity mappings. Both approaches were tested on three BIM models, to test their accuracy in identifying misclassifications. Results showed that outlier detection, which uses Mahalanobis distances, had difficulties when several types of dissimilar elements existed in a single IFC class and conversely was not applicable for IFC classes with insufficient number of elements. Novelty detection, using one-class SVM, was trained a priori on elements with dissimilar geometry. By creating multiple inlier boundaries, novelty detection resolved the limitations encountered in the former approach, and consequently performed better in identifying outliers correctly.