• Journal of People, Plants, and Environment
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• v.23 no.4
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• pp.387-398
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• 2020

Background and objective: Land vacancy is a persistent issue in most urban areas in the United States, yet few case studies have examined how vacant lots are used and the functions they serve in local communities. The purposes of this study were to provide a new revitalization planning and design proposal for the Durant-Tuuri-Mott (DTM) target area in the shrinking city of Flint, MI, USA, and to assess the final planning and design guideline through an analysis of vacant land redevelopment alternatives. Methods: For developing a revitalization planning and design guideline, this study developed several design modules with three main design themes. Then, landscape performance of the final design proposals was analyzed by three development scenarios, based on implementation level: 100%, 75%, and 50%. These development scenarios were based on the local context and different implementation budgets needed to adopt the proposed design modules. To generate a comprehensive development plan by optimizing design module allocation in the study area, this research employed a system-oriented approach, analyzing the existing cultural, natural, and built environments. A community participant process was adopted to collect stakeholders' opinions on future development. Results: By utilizing landscape performance metrics to quantify the environmental, social, and economic benefits, this study developed optimized development scenarios and a master plan for the reuse and redevelopment of existing vacant lots across DTM neighborhoods and analyzed the benefits of each. Conclusion: This research offers a flexible design method for balancing objectives in vacant land redevelopment that can be applied in other shrinking cities.

• Geomechanics and Engineering
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• v.31 no.6
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• pp.545-556
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• 2022

Evaluation and optimization of tunnel wall convergence (TWC) plays a vital role in preventing potential problems during tunnel construction and utilization stage. When convergence occurs at a high rate, it can lead to significant problems such as reducing the advance rate and safety, which in turn increases operating costs. In order to design an effective solution, it is important to accurately predict the degree of TWC; this can reduce the level of concern and have a positive effect on the design. With the development of soft computing methods, the use of deep learning algorithms and neural networks in tunnel construction has expanded in recent years. The current study aims to employ the long-short-term memory (LSTM) deep neural network predictor model to predict the TWC, based on 550 data points of observed parameters developed by collecting required data from different tunnelling projects. Among the data collected during the pre-construction and construction phases of the project, 80% is randomly used to train the model and the rest is used to test the model. Several loss functions including root mean square error (RMSE) and coefficient of determination (R²) were used to assess the performance and precision of the applied method. The results of the proposed models indicate an acceptable and reliable accuracy. In fact, the results show that the predicted values are in good agreement with the observed actual data. The proposed model can be considered for use in similar ground and tunneling conditions. It is important to note that this work has the potential to reduce the tunneling uncertainties significantly and make deep learning a valuable tool for planning tunnels.

• Journal of the Korean GEO-environmental Society
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• v.24 no.1
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• pp.45-50
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• 2023

In order to prevent slope disasters caused by rainfall, it is very important to quickly exclude rainfall. In Korea, horizontal drainage holes with excellent economic feasibility and construction performance are generally applied as a method to lower the underground water level. However, horizontal drainage holes constructed on the site are often uniformly constructed regardless of the presence or absence of other water or ground conditions, and it is often difficult to expect drainage performance of horizontal drainage holes due to poor maintenance. In this study, an artificial ground was created using model construction and horizontal drainage experiments were conducted to measure the amount of horizontal drainage drain in a certain amount of control area 0%, 25%, 50%, 75%, and an evaluation table (draft) that can quantitatively evaluate horizontal drainage based on measurements and design documents is proposed as basic data.

• Journal of the Korea Institute of Building Construction
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• v.23 no.1
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• pp.23-33
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• 2023

It is widely known that the level of fire resistance of wooden structure is determined by a charring rate or charring depth, and these are adopted for fire design. In this study, specimens of domestic larch column with a lamination wooden type were prepared and the fire resistance properties such as the charring depth, load ratio and the specific charring rate suggested by EN Code investigated. Test results showed that as expected, the weakest part was the corner of the column, so that the charring depth of the corner was deeper than the other parts of the column. For the load ratio less than 0.9, it had little effect on the charring depth.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.91-97
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• 2023

Aging construction machinery and vehicles with old diesel engines usually have a long life span, so they continue to emit harmful emissions. Therefore, replacing these older diesel engines with engines that meet the latest emisstion standard is expected to help improve air quality, and engines with propane fuels, which are easily available at construction sites, can be an appropriate alternative. In this study, a propane fueled engine was developed based on a 6.8-liter CNG engine, and technologies such as gas injectors, exhaust gas recirculation (EGR), and enhanced catalysts were applied. As a result, nitrogen oxides achieved half of the emission performance at the Stage-V level, the latest emission standard, while securing diesel engine output and torque in the same class.

• Smart Structures and Systems
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• v.34 no.3
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• pp.157-169
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• 2024

Accidents involving inland waterway vessels have raised concerns regarding monitoring their navigation tracks. The economical and convenient deployment of video surveillance equipment and computer vision techniques offer an effective solution for tracking vessel trajectories in narrow inland waterways. However, field applications of video surveillance systems face challenges of small object detection and the limited field of view of cameras. This paper investigates the feasibility of using multiple monocular cameras to monitor long-distance inland vessel trajectories. The one-stage CNN model, YOLOv5, is enhanced for small object detection by incorporating generalized intersection over union loss and a multi-scale fusion attention mechanism. The Bytetrack algorithm is employed to track each detected vessel, ensuring clear distinction in multiple-vessel scenarios. An inverse projection formula is derived and applied to the tracking results from monocular camera videos to estimate vessel world coordinates under potential water level changes in long-term monitoring. Experimental results demonstrate the effectiveness of the improved detection and tracking methods, with consistent trajectory matching for the same vessel across multiple cameras. Utilizing the Savitzky-Golay filter mitigates jitter in the entire final trajectory after timing-alignment merging, leading to a better fit of the dispersed trajectory points.

• The Korean Journal of Ceramics
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• v.6 no.2
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• pp.103-106
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• 2000

The effects of replacement level, curing method and chemical admixtures were investigated in the cement-fly ash paste. The strength of cement-fly ash paste is lower than that of controlled cement paste only and the differences increase with replacement level. However, in steam curing, strength of cement-fly ash pastes is improved, especially, at early ages. In order to improve early strength, the use of $Na_2SO_4$in cement-fly ash paste increases the quality of concrete. In addition, improvement of strength of concrete including 30% of fly ash can be obtained and achieves the highest strength compared to other concrete mixtures.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.345-348
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• 2007

People's income level is being ehanced, utilization of a car is increasing. Utilization of a car is increasing by peoples' income level elevation along with growth of economy. Economical loss and environmental pollution by vehicles stagnation of downtown are increasing. Specially, in case of downtown it is trend that the city traveling speed is decreasing every year. Lately, transfer bicycle-user to use public traffic is increasing. And they is using much on leisure because of physical strength improvement and the 5 day work week. In this study, we introduce examples of overseas designing and managing bicycle-user road based on GIS(a target of America and Canada). And we purpose construction-necessity of Bicycle Road Management System(BRMS) using GIS technique in domestic.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.447-454
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• 2003

In this test, two separated oil jacks were placed at bottom of drilled shaft(D = 1,500mm, L = 33m), and maximum upward and downward load of 1,250 tonf was applied. Also, the deformable rod sensors were placed on each level, and axial strains at each level were measured. Because the side skin friction and the end bearing could be measured separately in the Osterberg type pile load test, this test might be more economical and more applicable than a conventional static pile load test. Thus, if this Osterberg type pile load test could be established during design stage, construction cost might be reduced and its application for large diameter pile could be enhance greatly.

• The Journal of Society for e-Business Studies
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• v.4 no.3
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• pp.1-24
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• 1999

Strategic alliance between corporations is essential to build a CALS system. Specially, companies cooperate one another to accomplish the shared environment in the system. During the construction of the CALS system, we can apply the concepts of ILS and SCM to develop the breadth and depth of shared environment between firms. In order to build such intended environment in the CALS system, we propose five dimensions with 30 variables to be considered. These dimensions are Information Sharing, Task Sharing, System Sharing, Parts and Facilities Sharing, and Institution Sharing. Structured interviews were peformed to measure the degree of shared environment designed in 7 CALS pilot systems in Korea. The results show that the level of the shared environment in the context of vertical relationships between firms in the CALS systems is fairly high. In contrast, the level of the sharing between competing companies in horizontal relationships is relatively low in most of the pilot systems.