• Journal of Korean Society on Water Environment
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• v.36 no.5
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• pp.431-444
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• 2020

The relationship between dam construction and water quality has recently come to be considered an important issue. A dam is a physical factor which causes changes to the river system around it. Considering these points, this study was conducted to obtain basic data by analyzing the relationship between water level fluctuations and water quality parameters in the short-term. In terms of methodology, the new construction of the Yeongju Dam (M5) in 2016 was divided into Stage 1 as the lotic system and Stage 2 as the lentic system, with four years in each period, and the water level fluctuations and water quality were analyzed using official data. As a result of this study, M5, a stagnant area in which organic matter and nutrients accumulate, was found to be an important factor in water quality management. In addition, the water level changed rapidly (0.9±0.2 m → 10.9±7.1 m) as the river environment condition was converted from the lotic system to the lentic system. In addition, water quality parameters such as BOD, COD, TOC, and Chl-a significantly changed in the short-term. Further, since the transport of organic matter and nutrients occurred well in the lotic system, sedimentation was expected to be dominant in the lentic system. Therefore, it was determined that when the river flow is blocked, autochthonous organic matter is an important factor for long-term water quality management in the future. This process can increase the trophic state of the water body. As a result of this study, the TSI_KO value was converted from mesotrophic in Stage 1 to eutrophic in Stage 2. Eventually, short-term changes in the river environment will affect not only changes in water level but also changes in water quality. Thus, a comprehensive and strategic approach is needed for long-term water quality management in the future.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.1247-1248
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• 2022

Due to rapid urbanization and population growth, it has become crucial to analyze the various volumes and characteristics of pedestrian pathways to understand the capacity and level of service (LOS) for pathways to promote a better walking environment. Different indicators have been developed to measure pedestrian volume. The pedestrian level of service (PLOS), tailored to analyze pedestrian pathways based on the concept of the LOS in transportation in the Highway Capacity Manual, has been widely used. PLOS is a measurement concept used to assess the quality of pedestrian facilities, from grade A (best condition) to grade F (worst condition), based on the flow rate, average speed, occupied space, and other parameters. Since the original PLOS approach has been criticized for producing idealistic results, several modified versions of PLOS have also been developed. One of these modified versions is perceived PLOS, which measures the LOS for pathways by considering pedestrians' awareness levels. However, this method relies on survey-based measurements, making it difficult to continuously deploy the technique to all the pathways. To measure PLOS more quantitatively and continuously, researchers have adopted computer vision technologies to automatically assess pedestrian flows and PLOS from CCTV videos. However, there are drawbacks even with this method because CCTVs cannot be installed everywhere, e.g., in alleyways. Recently, a technique to monitor bio-signals, such as electrodermal activity (EDA), through wearable sensors that can measure physiological responses to external stimuli (e.g., when another pedestrian passes), has gained popularity. It has the potential to continuously measure perceived PLOS. In their previous experiment, the authors of this study found that there were many significant EDA responses in crowded places when other pedestrians acting as external stimuli passed by. Therefore, we hypothesized that the EDA responses would be significantly higher in places where relatively more dynamic objects pass, i.e., in crowded areas with low PLOS levels (e.g., level F). To this end, the authors conducted an experiment to confirm the validity of EDA in inferring the perceived PLOS. The EDA of the subjects was measured and analyzed while watching both the real-world and virtually created videos with different pedestrian volumes in a laboratory environment. The results showed the possibility of inferring the amount of pedestrian volume on the pathways by measuring the physiological reactions of pedestrians. Through further validation, the research outcome is expected to be used for EDA-based continuous measurement of perceived PLOS at the alley level, which will facilitate modifying the existing walking environments, e.g., constructing pathways with appropriate effective width based on pedestrian volume. Future research will examine the validity of the integrated use of EDA and acceleration signals to increase the accuracy of inferring the perceived PLOS by capturing both physiological and behavioral reactions when walking in a crowded area.

• Journal of architectural history
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• v.15 no.1 s.45
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• pp.7-27
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• 2006

This study aims to identify and analyze the factors that influenced the construction of London Eye which was led by private groups, including characteristics in progress, differentiated value in design, the combination of technology and design, and construction costs. The results of this study were the followings. 1) London Eye provides a new construction method for a landmark in the downtown in that the architects became the clients of the project which might have been hoarded, procuring the construction costs and completing it by themselves. 2) London Eye presents a space utilization method where undeveloped spaces in the downtown are used in three-dimensions by erecting a structure on the river with a minimum land. 3) The process of design, production and erection is propelled the realization of technical intention design with one system and from at the initial stage, the participation of the engineer where the designer is equal with you must accompany. 4) London Eye is endowed with strong shape by a circle in design concept, which is the simplest geometrical figure, and it provides organic relationship between the past and the present by utilizing historical elements in various ways. 5) The construction was completed through four phases including idea phase, promotion phase, turn-key contract phase, and design-build phase. The most critical factor to the success is derived from the direct contact with Involved companies from the production phase. 6) In a project facing many challenges in terms of technology, the design-build method proves to be a more effective method than turn-key contract in that it may more allocate risks and enable coherent implementation of the core concept in design. The organization for the design-build method was composed of three phases including general affairs, responsible contracting by sector, and cooperative system by sector. Since that was a new concept structure, high-level contractors who hadn't had existing cooperative relationships with one another formed new cooperative relationship, while collaborating companies who had long cooperated led the responsible contracting and sub-cooperative system, which resulted in reduction of risks and time. 7) The major factors to change design were the design characteristics, derived from a technically great combination, and the opening time. 8) A new erection method was applied to London Eye, a structure that overcame the limitation in land and period, and the process of installation demonstrated that it is an important value for the construction of a landmark in the city. 9) In spite of many visitors and tremendous operational income, the factors that London Eye fails to free itself from debts include the construction costs expended double than expected, and interest burden to the investments, which occurred in the course of procuring the costs. Absolute limit in time increased the construction costs, resulting in being a great obstacle in the course of operation.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.353-358
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• 2003

Recently there has been huge efforts to improve performance in construction process by applying emerging techniques such as the Lean principle, Just-in-time concept and so on. However, little achievement as we expected has come out in reality due to the lack of strategy to set a definite goal of the execution and differences of personal viewpoints on construction productivity. Accordingly, it is the most important to promote the circumstances for the construction process improvement by quantifying the goals of respective unit activity groups. This research explores feasible solutions for the improvement of construction projects performance by combining the six-sigma principle for the generic administrative innovation based on the idea of construction process performance. For this purpose, mutual comparisons of various current approaches are performed in an attempt to establish the advantages in applying six-sigma idea and to provide its fundamental strategy. Furthermore, through a case study with the simulation of applying six-sigma to a unit activity group in construction process, this paper verifies that the overall performance improves as the degree of sigma level gets advanced.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.136-145
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• 2018

Companies that have suffered serious labor shortages are relocating their factories abroad where they can solve this problem by increasing the employment of foreign workers. Construction sites also employ foreign workers to supplement the scarce manpower, and the demand for foreign workers has been gradually increasing over time. Recently, based on discussions on whether or not to introduce foreign workers, the policy on the input of foreign workers into domestic construction sites has been shifted to exploring the actual input conditions and efficient management methods. In this study, we investigated the current status and input situation of foreign workers at the construction sites of the target area, analyzed the problems they posed from the manager's viewpoint, and derived a method of improving the utilization of foreign workers at construction sites. In order to proceed with this study, we surveyed the actual situation of the construction sites, which consisted mainly of foreign workers and domestic workers (managers), by investigating the construction sites, and conducted 1: 1 interviews to ensure the reliability of the survey. The data obtained from the survey were analyzed using the SPSS analysis program, and the response rate was analyzed for each item. As a result, various problems, such as institutional problems, communication problems, and quality deterioration due to malfunction, appeared. Therefore, this study derives an improvement plan for the efficient utilization of foreign workers by improving the institutional level related to their language education, wages and employment.

• Korean Journal of Construction Engineering and Management
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• v.19 no.6
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• pp.124-134
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• 2018

Despite the many advantages of modular housing, low preference for modular housing for consumers who are familiar with RC structure leads to high construction cost of modular housing. The cost of modular buildings is about 130% of that of RC structures, so it is urgent to secure economical efficiency of modular buildings. Therefore, in this study, after calculating the savings amount of modular housing by type of construction work, economic analysis was conducted from a long - term perspective. In order to carry out the research, the authors compiled and analyzed the material cost, labor cost, and expenses incurred by each type of work by reclassifying the statement of the modular housing into the factory production and the site installation. After that, Pareto diagrams were created to find a core work that is included in the cost ratio of about 80%, and selected it as a cost reduction subject. Based on the assumption that the market size of domestic modular housing is similar to the level of modular advanced countries such as Japan and European countries, six cost reduction methods were set up that reflects the characteristics of the modular construction method and used for the expert interviews. Cost saving potentials in percentage from the interview were converted to the amount of savings that can be achieved by each type of method when applying the method. Finally, the findings of the study are expected to suggest long-term directions for technical development for modular construction and cost savings.

• Korean Journal of Construction Engineering and Management
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• v.11 no.6
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• pp.100-110
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• 2010

The main roots of CM service contracts include existing customer repurchases and those made by new customers by existing ones. The study on customers and loyalty can be factors to strengthen CM's competitiveness. However, there have been little attempt to study customer satisfaction and customer loyalty. Construction Management (CM), the advanced construction management method, was introduced 15 years ago in the mid 1990's in the domestic market. The aim of this research is to build a model that can predict customer loyalty based on how much customers are satisfied with CM service. To measure customer satisfaction and loyalty, this research surveyed 135 decision-makers who have experienced CM services. Customer satisfaction was tested and analyzed according to different phases: planning, designing, procurement, construction, and post construction. Referral intention was tested based on NPS theory. Customer types were divided into detractors, passively satisfied and promoters according to the tested measurement and multinomial logistic regression between the satisfaction by construction phases and customer types. This research resulted to a model that can predict customer types: detractors, passively satisfied and promoters, which were determined according to satisfaction level. The initial planning phase also revealed which factor is most influential for a customer to become promoter. These results can be used to acquire customer loyalty by managing the satisfaction of customers through a project under an Internet-based environment. Such can provide the needed information in quickly exploring positive and negative word-of-mouth feedbacks.

• Korean Journal of Construction Engineering and Management
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• v.16 no.3
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• pp.59-67
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• 2015

Overseas expansion of domestic construction over the past 10 years has been fast growing. But as a result of simple construction business practices and a focus on EPC, sales margins was reduced. Domestic construction companies have been trying to redirect business to high-value-added-areas but have faced difficulty because there areas are current monopolized by global leading companies in the field of PMC. They have recently carried out 16 PMC related project in order to expand their experience and increase their competitiveness. Most of these construction companies that do PMC overseas have been focusing on the civil engineering sector. analyzing the important and performance result 50 separate PMC tasks in detail using IPA, it became clear that domestic construction companies should also focus on tasks and were analyzed in order to advance to overseas architecture PMC sector overseas. There are large gaps in the importance and performance result of both the planning and pre-construction phase. Importance compared to the current performance levels in the planning phase gap is largest, pre-construction phase has been analyzed in the following order. In particular, one should strengthen detailed tasks in the planing phase. This study is expected to be used as a basic to determine the performance level and tasks items. It is expected strengthen the capacities of domestic companies in the PMC field, for especially in the high value-aded-areas as indicated in the results of the analysis from this study.

• Journal of agricultural medicine and community health
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• v.40 no.2
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• pp.80-92
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• 2015

Objectives: To clarify the association between dust from large construction sites and allergic and respiratory conditions among residents in Sejong city. Methods: We included 379 individuals older than 50 years from three areas of Sejong city; two areas near construction sites and one area for a comparison. Prevalence of self-reported allergic and respiratory conditions was compared across the three areas using logistic regression to adjust for covariates including age, gender, smoking, and educational attainment. A total of 16 individuals were interviewed to take details of the residents' experiences of construction work. Results: Those living in the nearby areas around construction sites were generally found to have the increased prevalence for all allergic and respiratory conditions. Odds Ratio(OR)s for cough and sneezing among the six symptoms and allergic rhinitis among the three diagnosed diseases reached statistical significance but only OR for cough remained significant after adjustment: adjusted OR for cough was 2.63 (95% CI, 1.07-6.46). Two relevant themes emerged from semi-structured interview were; 1) most residents from the affected area reported a considerable level of exposure to construction dust, 2) about half of them noted that construction dust influences allergic- and respiratory health. Conclusions: General pattern provides suggestive evidence that living close to construction sites may be positively associated with elevated risks of allergic and respiratory conditions. Efforts should be made to establish preventive measures and a comprehensive in-depth health impact assessment on this issue.

• The Journal of the Korea Contents Association
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• v.18 no.12
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• pp.432-443
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• 2018

This study aims to analyze the current career management system for construction engineers and propose the developed future plan for the career management system. Especially, this study explores the Index of Construction Engineer's Competency(ICEC) and issues for workplace competency development which is the foundation of the career management system for construction engineers and proposes the advanced strategies for operating the career management system. For the developing the future strategy of the current construction engineer's career management system, a focus group interview was conducted in this study. Total 12 experts participated in the FGI. The study results identify the six key issues for advanced construction engineers' career management system. Those six issues include 1)preparing in the inducement of new human resources, 2)institutional modification of the current job/expertise fields, 3)attaching importance of practical experience in the workplace, 4)consideration of various factors of individual career, and 5)developing the highest level's workplace competency. Based on these research findings, theoretical and practical implication and suggestion for future studies were provided.