• Journal of the Korean Geosynthetics Society
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• v.17 no.3
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• pp.19-32
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• 2018

Gravel Compaction Pile (GCP) method is currently being designed and constructed by empirical method because quantitative design method has not been developed, leading to various types of and frequent destruction such as expansion failure and shear failure and difficulties in establishing clear cause and developing measure to prevent destruction. In addition, despite the difference with domestic construction equipment and material characteristics, the methods applied to the overseas ground is applied to the domestic as it is, leading to remarkable difference between applied values and measured values in variables such as bearing capacity and the settlement amount. The purpose of this study was, therefore, to propose a reasonable and safe design method of GCP method by analyzing the settlement and stress behavior characteristics according to ground strength change under GCP method applied to domestic clay ground. For the purpose, settlement amount of composite ground, stress concentration ratio, and maximum horizontal displacement and expected location of GCP were analyzed using ABAQUS. The results of analysis showed that the settlement and Settlement reduction rate of composite ground decreased by more than 60% under replacement ratio of 30% or more, that the maximum horizontal displacement of GCP occurred at the depth 2.6 times pile diameter, and that the difference in horizontal displacement is slight under replacement ratio of 30%.

• Architectural research
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• v.17 no.4
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• pp.127-137
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• 2015

A typology study is a comparative study of the physical characteristics of the built environment divided into distinct types such as architecture, culture, and environment. Lao vernacular dwellings were initially created based on the Lao people's behavior in terms of beliefs, traditional culture, lifestyle, and local wisdom with regard to the environment, climate, geography, and materials. The main research method used in this study is a comparative case study of three ethnic dwellings. The multiple data collection tools employed included second source data and primary data to analyze the findings of the unique characteristic typology of Lao vernacular dwellings. The objective of this paper is to compare the cultural and physical contexts, the patterns and origins of settlement, the architecture, the cultures, and the local indigenous knowledge related to the dwellings and settlement of the three main ethnic groups. These three groups are rich in tradition and their documentation is therefore essential for the intellectual history of the society of Lao; this research could therefore aid in enhancing our understanding of the three typologies of Lao vernacular architecture and settlement within the historical and sociocultural contexts of each ethnicity to convey an understanding of Lao vernacular dwellings by analyzing their different types to help identify the differences and similarities among architectural artifacts by recognizing the invisible connections between them, whereby the figurative ornamentation is based on the relationship between man and nature. This study also provides a glimpse of the living culture and characteristic features of Lao vernacular architecture.

• Geomechanics and Engineering
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• v.12 no.4
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• pp.689-705
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• 2017

The present study deals with the Pressure-settlement behavior of square and rectangular skirted footing resting on sand and subjected to a vertical load through a laboratory experimental study. A series of load tests were conducted in the model test tank to evaluate the improvement in pressure-settlement behavior and bearing capacity of square and rectangular model footings with and without structural skirt. The footing of width 5 cm and 6 cm and length/width ratio of 1 and 2 was used. The relative density of sand was maintained at 30%, 50%, 70%, and 87% respectively. The depth of skirt was varied from 0.25 B to 1.0 B. All the tests were carried out using a strain controlled loading frame of 50 kN capacity. The strain rate for all test was kept 0.24 mm/min. The results of present study reveal that, the use of structural skirt improves the bearing capacity of footing significantly. The improvement in bearing capacity was observed almost linearly proportional to the depth of skirt. The improvement in bearing capacity of skirted footings over footing without skirt was observed in the range of 33.3% to 68.5%, 68.9% to 127% and 146.7% to 262% for a skirt depth of 0.25 B, 0.50 B and 1.0 B respectively. The skirted footings were found more effective for sand at relative density of 30% and 50% than at relative density of 70% and 87%. The bearing capacity was found to increase linearly with footing width for footings with and without skirts. This observation was found to be consistent for footings with different skirt depths and for relative density of sand i.e., 30%, 50%, 70%, and 87%. The obtained results from the study for footing with and without skirts were comparable with available solutions from literature.

• Journal of the Korean GEO-environmental Society
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• v.13 no.10
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• pp.85-94
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• 2012

Recent development trend of construction projects in the urban area is the efficient use of insufficient land, however caused to difficult construction conditions because of many adjacent structures. This paper presents the case study that analyzed the ground settlement of railroad structure for the double track railway project of Gyeongui line, adjacent to the high rise building under ground excavating for substructure work, considering interaction of soft ground characteristics. Field survey and measurement works were carried out during construction of station and excavation of high rise building, and field data were analyzed to find the source of settlement of platform and railway. In addition, the soil reinforcement and foundation restoration were performed using in-situ injection method, i.e., D-ROG(Digitalized Restoring On Grout) method which filled the pore of bottom and around of foundation with micro-cement.

• The Journal of Engineering Geology
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• v.29 no.3
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• pp.211-222
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• 2019

This study evaluates the yield load and allowable bearing capacity of ground in compressive loading tests to confirm the effect of CPR foundation reinforcement. The average compressive strength of the injection materials was higher than the planned compressive strength. Standard penetration tests for each stratum showed that foundation reinforcement improved the average N values, thereby increasing the bearing capacity of the ground. Compressive loading tests on two CPR piles revealed that the total and net settlement due to the maximum load exceed that permissible for the CPR pile diameter. The yield load and allowable bearing capacity calculated by the settlement criterion and the load-settlement curves varied greatly with the method applied. Therefore, it seems to be necessary to determine the optimum value through comprehensive analysis after applying various yield load calculation methods.

• Geomechanics and Engineering
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• v.38 no.5
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• pp.517-528
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• 2024

For numerous tunnelling projects implemented in urban areas due to limited space, it is crucial to take into account the interaction between the foundation, ground, and tunnel. In predicting the deformation of piled foundations and the ground during twin tunnel excavation, it is essential to consider various factors. Therefore, this study derived a prediction model for pile group settlement using machine learning to analyze the importance of various factors that determine the settlement of piled foundations during twin tunnelling. Laboratory model tests and numerical analysis were utilized as input data for machine learning. The influence of each independent variable on the prediction model was analyzed. Machine learning techniques such as data preprocessing, feature engineering, and hyperparameter tuning were used to improve the performance of the prediction model. Machine learning models, employing Random Forest (RF), eXtreme Gradient Boosting (XGB), and Light Gradient Boosting Machine (LightGBM, LGB) algorithms, demonstrate enhanced performance after hyperparameter tuning, particularly with LGB achieving an R² of 0.9782 and RMSE value of 0.0314. The feature importance in the prediction models was analyzed and P_N was the highest at 65.04% for RF, 64.81% for XGB, and P_CTC (distance between the center of piles) was the highest at 31.32% for LGB. SHAP was utilized for analyzing the impact of each variable. P_N (the number of piles) consistently exerted the most influence on the prediction of pile group settlement across all models. The results from both laboratory model tests and numerical analysis revealed a reduction in ground displacement with varying pillar spacing in twin tunnels. However, upon further investigation through machine learning with additional variables, it was found that the number of piles has the most significant impact on ground displacement. Nevertheless, as this study is based on laboratory model testing, further research considering real field conditions is necessary. This study contributes to a better understanding of the complex interactions inherent in twin tunnelling projects and provides a reliable tool for predicting pile group settlement in such scenarios.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.952-957
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• 2004

Cut and Cover Method is generally used in shallow tunnels and tunnel entrances with thin soil cover. In this type of cons0truction, backfilling is considered to be the most important process. In this process even though the backfill material is thoroughly compacted, compaction and self-weight due to vehicular vibration and pressure exerted by the soil cause the backfill material to undergo self-compression which leads to settlement. The settlement of the backfill material subjects the tunnel lining under excessive earth pressure which cause cracking and deformation. In the model test performed installation of geotextile on the sides and top of the tunnel was able to reduce the earth pressure acting on the tunnel lining.

• The Transactions of the Korea Information Processing Society
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• v.7 no.5S
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• pp.1657-1665
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• 2000

Mobile agents based e-commerce system has many advantage than traditional e-commerce-information gathering on goods, price settlement and payment, delivery of the goods purchased, and so on. However, due to the security vulnerability that stems from mobile agent's mobility, mobile agents based e-commerce system has additional security problems. Therefore, in order to do e-commerce securely in th system, first of al the security issues on mobile agents must be addressed. It this paper, we propose a mobile agent transfer protocol that provides confidentiality and integrity of mobile agent in transit and mutual authentication for communicating hosts. We further show the security of the protocol against many possible attacks. Also, we suggest the location management mechanism of mobile agents based on the trust center. This mechanism is capable of finding their locations transparently and detecting mobile agent clones.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.365-370
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• 2004

At the present, e-commerce takes the place of existing transaction form in structure in the world trade by advancement of Information Technology and diffusion of Internet. There is no exceptions of this tendency even in industry of maritime and logistics. So, global shipping lines and logistics companies try to construct the e-Business network system for increasing their competitiveness in an are of cyber. However, in Korea, most of companies prefer "final handshake" as the traditional way of transaction to "e-commerce", because they bear a distrust in mind about the outflow of transaction information and security of settlement. So, number of companies using e-commerce is very small, and this situation causes the limited factor for activating the transaction structure of it. The rate of using e-commerce in logistics industry is lower than other industries, even more higher effectiveness is expected when they use it. Especially, it is very necessary not only e-commerce but also e-Logistics which can serve information of freight cost on cargo flow, operation cost and schedule, and tracing information of cargo. Increasing the necessity of e-Logistics, this study research the rate rf using e-Logistics focused on maritime and logistics companies, and analyze the transaction form among members of these industries for improving them. In detail, this paper examine the drivers for activating e-Logistics, and present the effective factors for a successful development of these industries.

• International Journal of Advanced Culture Technology
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• v.11 no.2
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• pp.125-131
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• 2023

OVO is a digital platform that provides simple payments and smart financial services, as well as one of the largest digital payment platforms in Indonesia. It has wide coverage and security when making payments, and supports multiple settlement currencies. The purpose of this study is to explore the history, business model, and future strategic direction of OVO, an Indonesian e-wallet. To date, OVO has built its own mobile payment ecosystem covering a wide range of consumer scenarios including e-commerce, travel, offline shopping and finance. And it supports mobile banking, online banking, debit cards or selected partner merchants. Its three largest transaction categories are in the transportation, retail and e-commerce sectors. With over 110 million consumers and 1.3 million merchant users, it is one of the dominant e-wallets in Indonesian market and has become the country's e-payment market leader. OVO eWallet's 'One Card' model offers convenience and choice for users, thus contributing to the rapid growth of OVO eWallet. And OVO eWallet competes fiercely with other competitors, but OVO eWallet continues to grow in terms of the number of users and market share. Finally, this study analyzes the strategic goals and plans of OVO eWallet, predicts its future direction. OVO eWallet has a huge success, but there are still competition and challenges to face.