• International conference on construction engineering and project management
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• 2009.05a
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• pp.1485-1490
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• 2009

This paper discusses cases of infrastructure asset management in the U.S., Canada, and Australia and investigates infrastructure management in Korea in order to set the direction for the asset management improvement. The definitions of infrastructure asset management from various entities are introduced and implementation framework and organizational structures are described. The investigation on Korean public asset management practices finds the strong and weak points and defines the requirements and considerations to further improve the current practices. This paper will assist adopting infrastructure asset management in Korea and provide guide for the infrastructure maintenance.

• Korean Journal of Construction Engineering and Management
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• v.12 no.2
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• pp.53-63
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• 2011

The repetitive occurrence of similar accident is one of the biggest feature in construction disasters. Similar accident cases provide direct information for finding risk of scheduled activities and planning safety countermeasure. Many systems are developed to retrieve and use past accident cases by researchers. However, these researches have some limitations for performing too much retrieval to obtain results considering construction site conditions or not reflecting characteristics of safety planning steps or both. To overcome these limitations, this study proposes accident case retrieval system that can search similar accident cases. It also helps safety planning using information retrieval and building information modeling. The retrieval system extracts BIM objects and composes a query set combining BIM objects with site information DB. With past accident cases DB compares a query set, it seeks the most similar case. And results are provided to safety managers. Based on results of this study, safety managers can reduce excessive query generation. Furthermore, they can be easy to recognize risk of a construction site by obtaining coordinations of objects where similar accidents occurred.

• Journal of the Korean Institute of Rural Architecture
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• v.24 no.2
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• pp.29-36
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• 2022

This study analyzed the effects of building and greenhouse structural code on the structural design and the greenhouse construction cost. The over-design possibility of greenhouse was analyzed when building structural code was applied using standard smart greenhouse drawings. The possibility of decrease in greenhouse construction cost was investigated if the currently applied building structural code was replaced with greenhouse structural code. As a result of comparing the member sizes with the standard drawings, building structural code was designed with 13%~74% more steel than greenhouse structural code. When building construction estimate was replaced with greenhouse construction estimate, it was possible to reduce the total construction cost of the glass greenhouse by 17% and that of the vinyl greenhouse by 14%. Since there is no standard construction estimate suitable for greenhouses, the wage unit price is set excessively, and the construction cost of the smart greenhouse is increasing. In conclusion, it is necessary to establish greenhouse structural code and greenhouse construction estimate to lower the greenhouse construction cost.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.3 s.168
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• pp.68-77
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• 2005

The set-up of an injection molding process is a ye complicated and time-consuming job because it is required to well determine a lot of variables closely related to products. Thus, the productivity of the set-up process mainly depends on operators' expertise and know-how. To solve the problem mentioned before, this research constructs a support system which helps operators determining the condition of the injection molding easily and systematically. The construction of the support system consists of the following four steps: 1) to determine the control variables which affect the target defect types, 2) to design and implement UI(user interface) using a scenario of set-up process, 3) to design and implement the search algorithms for the initial and optima] condition, and 4) to construct the embedded system which integrates the support system with the operating system of a plastic injection molding machine. The test experiments of some typical products are performed using the embedded system to verify the validity of the support system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.470-473
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• 2007

Wireless Sensor Networks (WSNs) have merged to become one of the most promising applications of wireless ad hoc networks. A defer timer has been used in some of existing network protocols to solve a set of problems in WSNs. We first investigate the use of a defer timer to fully take the advantage of it in WSNs. We demonstrate that by properly setting up the defer timers, many difficult issues in sensor networks, such as power limitation, the broadcast storm problem, and the construction of the virtual backbone, can be easily tackled with only the help of simple localized information at each node. In this paper, we present the power of a defer timer in the design of dominating set construction protocol for broadcasting. The ns 2 computer simulations are carried out for performance study.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.147-147
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• 2018

In this article, we use an open source software library: TensorFlow, developed for the purposes of conducting very complex machine learning and deep neural network applications. However, the system is general enough to be applicable in a wide variety of other domains as well. The proposed model based on a deep neural network model, LSTM (Long Short-Term Memory) to predict the river water level at Okcheon Station of the Guem River without utilization of rainfall - forecast information. For LSTM modeling, the input data is hourly water level data for 15 years from 2002 to 2016 at 4 stations includes 3 upstream stations (Sutong, Hotan, and Songcheon) and the forecasting-target station (Okcheon). The data are subdivided into three purposes: a training data set, a testing data set and a validation data set. The model was formulated to predict Okcheon Station water level for many cases from 3 hours to 12 hours of lead time. Although the model does not require many input data such as climate, geography, land-use for rainfall-runoff simulation, the prediction is very stable and reliable up to 9 hours of lead time with the Nash - Sutcliffe efficiency (NSE) is higher than 0.90 and the root mean square error (RMSE) is lower than 12cm. The result indicated that the method is able to produce the river water level time series and be applicable to the practical flood forecasting instead of hydrologic modeling approaches.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.3
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• pp.27-33
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• 2021

Reclaimed land was mainly used as agricultural land for rice production. As a higher value-added business in the agriculture has recently been activated, green houses are being constructed. In case of green house construction on the reclaimed land, it is generally soft ground with high soil water content, so it is important to design the foundation for greenhouse construction. The object of this study, a pull-out test was conducted to derive the base line data of the wooden pile foundation when constructing a green house. To reproduce the actual site, 30% of soil saturation and 70% of soil saturation were created in the soil box. Groove number and depth were set as design factors of the wooden pile, and a pull-out test was conducted. As a result of the test, pull resistance increased as the number of grooves increased, pull-out resistance according to groove depth was different according to soil saturation. Also, after the experiment, we want to compare the set-up effects over time.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.57-58
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• 2022

Concrete mix design is used as essential data for the quality of concrete, analysis of structures, and stable use of sustainable structures. However, since most of the formulation design is established based on the experience of experts, there is a lack of data to base it on. are suffering Accordingly, in this study, the purpose of this study is to build a predictive model to use the concrete mixing factor as basic data for calculation using the DNN technique. As for the data set for DNN model learning, OPC and ternary concrete data were collected according to the presence or absence of admixture, respectively, and the model was separated for OPC and ternary concrete, and training was carried out. In addition, by varying the number of hidden layers of the DNN model, the prediction performance was evaluated according to the model structure. The higher the number of hidden layers in the model, the higher the predictive performance for the prediction of the mixing elements except for the compressive strength factor set as the output value, and the ternary concrete model showed higher performance than the OPC. This is expected because the data set used when training the model also affected the training.

• Journal of the Korean Society of Safety
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• v.28 no.5
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• pp.27-34
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• 2013

Almost accidents in construction sites are occurred by unsafe work conditions and failure making safe environment. As recent construction projects become more complex, various and diversified, So the potential of construction-related accidents is increased as well. Comparing the frequency of construction-related accidents in large-sized construction sites, small-sized construction sites are more vulnerable because of lack of workforce and less effective technology system. Furthermore, the absence of safety committee, poor financial condition leads to lack of safety education, installation of safety facilities, and provision of individual protective equipment, which indicates difficulties handling even basic safety management. Therefore, in order to lower the hazard rate at small-Sized construction sites, it is necessary to proceed with more structural and thorough actions for preventing accidents. In other words, it is necessary to analyze the causes of the accidents at small-sized construction sites, set criteria for safety management, and suggest safety management items according to work classification by evaluating the relative importance of the items.

• Journal of the Korea Institute of Building Construction
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• v.11 no.2
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• pp.200-207
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• 2011

Construction management services have been adopted for more than a decade and are continuously growing; however, the advantages of utilizing a construction management service are still not quite clear, regardless of many arguments can be made in their favor. The construction manager, as a coordinator, is supposed to smoothly facilitate the project teamwork in order to deliver a profitable and satisfactory project, not only for the owner's interests but also for the success of all project participants. This study has focused on the teamwork supports a construction manager can provide during project operations. This study developed a benchmarking tool to assess the construction manager's role in terms of its project teamwork supports, by utilizing the evaluation model and several case studies. In addition, this study also attempted to set the industry average and higher performance so that both the owner and the construction manager can self-assess, and more importantly, can improve project operation. The actual implementation of the benchmarking tool into on-going projects can allow the construction manager to understand the current operation and to make a better project process through teamwork.