Effect of Osteoconductive Hyaluronate Hydrogels on Calvarial Bone Regeneration

11Yscopu

Development of an approximate construction duration prediction model during the project planning phase for general office buildings

Accurate prediction of the construction duration is imperative to the reliable cash flow analysis during the project planning phase when feasibility analysis is carried out. However, lack of information and frequent changes that occur as a result of a negotiation process between the owner and the designer in defining the project scope make it difficult to compute real-time construction duration. Domestic and foreign models for calculating the construction durations cannot be readily applied to computation of construction duration for general office buildings in Korea specifically during the project planning phase as there is a limit in its applicability due to numerous restrictions. Moreover, there are no preceding studies suggesting different computational approaches to predict the entire construction duration for office buildings with the approximate construction duration concept during planning phase. Therefore, based on the collected performance data, this study proposes a multiple linear regression model that facilitates reliable prediction of approximate construction duration for office buildings in the project planning phase. The model will allow the owner and other stakeholders to predict the real-time construction duration using the basic information on office buildings and to assess the construction durations incorporating frequent changes during the project planning phase

Graphene Q-switched Yb:KYW planar waveguide laser

A diode-pumped Yb:KYW planar waveguide laser, single-mode Q-switched by evanescent-field interaction with graphene, is demonstrated for the first time. Few-layer graphene grown by chemical vapor deposition is transferred onto the top of a guiding layer, which initiates stable Q-switched operation in a 2.4-cm-long waveguide laser operating near 1027 nm. Average output powers up to 34 mW and pulse durations as short as 349 ns are achieved. The measured output beam profile, clearly exhibiting a single mode, agrees well with the theoretically calculated mode intensity distribution inside the waveguide. As the pump power is increased, the repetition rate and pulse energy increase from 191 to 607 kHz and from 7.4 to 58.6 nJ, respectively, whereas the pulse duration decreases from 2.09 μs to 349 ns

Development of construction duration prediction model for project planning phase of mixed-use buildings

The nature of the mixed-use building’s characteristics should be considered to calculate a proper construction duration for mixed-use buildings in the project planning phase. However, the existing construction duration prediction models are incapable to reflect nature as they were developed mainly for single-use buildings. Therefore, the purpose of this study was to suggest a multiple linear regression model for mixed-use buildings that can help the owner and contractor predict a proper construction duration in the project planning phase. To do so, 1,969 mixed-use building project data were collected. The final prediction model for mixed-use buildings with five independent variables was suggested in this study. Its R2 was 0.637 and Ra2 was 0.635. In addition, the results of the validation showed that the prediction model’s average prediction accuracy, MAPE, and RMSE were 88.51%, 75.94, and 11.49% respectively. Given that the prediction model is applied in the project planning phase when there is insufficient information on the project, the results are believed to be at a considerably reliable level. This prediction model will allow the end-user to make simple and quick predictions of a construction duration of a mixed-use building based only on the basic information in the project planning phase

3D surround local sensing system H/W for intelligent excavation robot (IES)

The recently developed intelligent excavation robot in Korea is a fully automated excavator equipped with global 3D modeling capabilities for an entire earthwork site and an intelligent task planning system. The intelligent excavation robot includes features such as autonomous driving, 3D surround modeling, autonomous excavation, loading, etc. An intelligent excavation robot features technology that allows for accurate recognition of objects near the excavator, including the terrain of surrounding environments, location of obstacles in the excavator’s path, and any approaching trucks and moving people. Such technology is critical to ensuring work quality and safety. In this study, we develop the hardware for a 3D surround laser sensing system that enables 3D image modeling of the terrain surrounding an intelligent excavation robot. By mounting a sensor onto an intelligent excavation robot, we conducted performance tests to determine the robot’s 3D modeling capabilities of the terrains and obstacles at an actual earthwork site. The experimental results are applied to an object recognition system for detecting the properties of the terrain of the workspace around the excavator, any approaching people, trucks, obstacles, etc. The proposed hardware includes a wide range of applications in the development of future automated construction equipment

Final detailed design of an all-in-one attachment-based PHC pile head cutting robot and its structural stability analysis

Conventional pretensioned spun, high-strength concrete (PHC), pile head cutting process is associated with safety, quality uniformity, and labor productivity problems. However, trend analysis has revealed that no technology has been developed to address these problems as these pertain to specific Korean construction site situations. This study aims to derive the final detailed design for an all-in-one attachment-based PHC pile head cutting robot, and analyzes its structural stability. To this end, the key functions of an all-in-one attachment-based PHC pile head cutting robot have been defined, and the related core element technologies have been analyzed. This has led to the presentation of two detailed design alternatives. Both of these were then subjected to an analytical hierarchal process (AHP) and trade-off analysis that led to the final selection of the diamond wheel saw-based detailed design. In a structural stability analysis of the final detailed design, all tested parts did not surpass the threshold yield strengths of 230 MPa (SS400) and 255 MPa (AL6061 T6). If a prototype is developed based on the final detailed design derived in this study, it is expected to have improved work safety, quality uniformity, and work efficiency characteristics compared with the conventional PHC pile head cutting process

Life Cycle Cost Analysis of the Steel Pipe Pile Head Cutting Robot

Steel pipe pile head cutting work is performed to adjust the horizontal levels of piles, and it is essential for the stable transfer of an upper structure load to the ground. However, the field survey results show that steel pipe pile head cutting process is highly dangerous as laborers especially deal with gas and plasma cutting machines. Moreover, the laborers are exposed to continuous risks because the piles are frequently felled, lifted, moved, and loaded using construction equipment, such as excavators, immediately after the piles are cut. Recently, the authors of this study developed a prototype of a steel pipe pile head cutting robot and verified its performance through laboratory experiments to improve work safety, productivity, and the quality of steel pipe pile head cutting work. The purpose of this study is to secure the economic feasibility of robot development and verify the sustainable utilization of a developed robot by analyzing the comprehensive performance and economic efficiency throughout the life cycle of a steel pipe pile head cutting robot developed in South Korea. In this study, sensitivity analysis was also performed on the variables expected to have a significant influence or variables that must be considered for the future commercialization of the developed robot. When the developed robot is applied to construction sites in the future, its ripple effects will be significant because it will be possible to prevent labor safety accidents, improve work productivity, secure uniform quality, and reduce input costs