• Journal of the Korean Geotechnical Society
• /
• v.30 no.2
• /
• pp.65-76
• /
• 2014

For soil improvement, sand mats or sand compaction piles are often constructed on soft marine clays. In such cases, some amounts of sand and clay are inevitably mixed. Sand or gravel often exists in the weathered soils near the slope surface. This research investigates the effect of mixing sand content on consistency limits and shear strength of clays. Firstly, sand was mixed with kaolinite or bentonite at 0, 9, 17, 23, 29, 33, 50% and then liquid and plastic limits were measured. Both plastic and liquid limits decreased as a sand content increased. The water content of clay-sand mixtures with different sand content increased by 10% or 20% step by step and then their undrained shear strength was measured using a portable vane shear device called Torvane. For all cases, undrained shear strength of clay-sand mixtures decreased rapidly until reaching a certain value. Their state changed from undrained to drained state gradually as the sand content increased, which caused their undrained shear strength to decrease. On the other hand, a series of direct shear tests were also conducted on such clay-sand mixtures to investigate the effect of sand content on cohesion and angle of internal friction. It was found from clay-sand mixtures that their cohesion decreased but angle of internal friction increased as the sand content increased.

• Journal of the Korean Geotechnical Society
• /
• v.28 no.10
• /
• pp.79-88
• /
• 2012

Small amount of salt and various microorganisms are contained in natural soils or clays near the shore. In this study, most common clay minerals such as kaolinite and bentonite are used to evaluate the effect of salt and microorganism on liquid and plastic limits. The effect of time after mixing clays with water was also investigated for the consistency limits of clays. The test was conducted immediately, 1 day, or 7 days after mixing soils. For liquid limit tests two different test methods were used, the percussion cup method by Casagrande and the fall cone method. When sea water or microbial solution was used for mixing soils rather than distilled water, the liquid limit of kaolinite decreased by 6-15% and that of bentonite further decreased up to 37-53%. The liquid limit obtained from the fall cone method was approximately 10% for bentonite and 20% for kaolinite, which are higher than those from the percussion cup method. The effect of time on liquid and plastic limits was significant for those tested immediately or 1 day later but the values obtained after 1 day or 7 days did not vary a lot, regardless of soils, mixing waters or test methods.

• Korean Journal of Logic
• /
• v.8 no.2
• /
• pp.3-32
• /
• 2005

Hilbert's rational ambition to establish consistency in Number theory and mathematics in general was frustrated by the fact that the statement itself claiming consistency is undecidable within its formal system by $G\ddot{o}del's$ second theorem. Hilbert's optimism that a mathematician should not say "Ignorabimus" ("We don't know") in any mathematical problem also collapses, due to the presence of a undecidable statement that is neither provable nor refutable. The failure of his program receives more shock, because his system excludes any ambiguity and is based on only mechanical operations concerning signs and strings of signs. Above all, $G\ddot{o}del's$ theorem demonstrates the limits of formalization. Now, the notion of provability in the dimension of syntax comes to have priority over that of semantic truth in mathematics. In spite of his failure, the notion of algorithm(mechanical processe) made a direct contribution to the emergence of programming languages. Consequently, we believe that his program is failure, but a great one.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.51 no.3
• /
• pp.299-309
• /
• 2024

This study aimed to assess the competency of artificial intelligence (AI) in pediatric dentistry and compare it with that of dentists. We used open-source data obtained from the Korea Health Personnel Licensing Examination Institute. A total of 32 item multiple-choice pediatric dentistry exam questions were included. Two AI-based chatbots (ChatGPT 3.5 and Gemini) were evaluated. Each chatbot received the same questions seven times in separate chat sessions initiated on April 25, 2024. The accuracy was assessed by measuring the percentage of correct answers, and consistency was evaluated using Cronbach's alpha coefficient. Both ChatGPT 3.5 and Gemini demonstrated similar accuracy, with no significant differences observed between them. However, neither chatbot achieved the minimum passing score set by the Pediatric Dentistry National Examination. However, both chatbots exhibited acceptable consistency in their responses. Within the limits of this study, both AI-based chatbots did not sufficiently answer the pediatric dentistry exam questions. This finding suggests that pediatric dentists should be aware of the advantages and limitations of this new tool and effectively utilize it to promote patient health.

• Journal of KIISE:Computing Practices and Letters
• /
• v.10 no.2
• /
• pp.134-145
• /
• 2004

With rapid growth in the amount of data transferred on the Internet, traditional storage systems have reached the limits of their capacity and performance. SAN (Storage Area Network), which connects hosts to disk with the Fibre Channel switches, provides one of the powerful solutions to scale the data storage and servers. In this environment, the maintenance of data consistency among hosts is an important issue because multiple hosts share the files on disks attached to the SAN. To preserve data consistency, each host can execute the disk I/O whenever disk read and write operations are requested. However, frequent disk I/O requests cause the deterioration of the overall performance of a SAN cluster. In this paper, we introduce a SANtopia global buffer manager to improve the performance of a SAN cluster reducing the number of disk I/Os. We describe the design and algorithms of the SANtopia global buffer manager, which provides a buffer cache sharing mechanism among the hosts in the SAN cluster. Micro-benchmark results to measure the performance of block I/O operations show that the global buffer manager achieves speed-up by the factor of 1.8-12.8 compared with the existing method using disk I/O operations. Also, File system micro-benchmark results show that SANtopia file system with the global buffer manager improves performance by the factor of 1.06 in case of directories and 1.14 in case of files compared with the file system without a global buffer manager.

• Journal of KIISE
• /
• v.43 no.6
• /
• pp.668-677
• /
• 2016

The information superiority through effective networking is a core element that accelerates command decision for mission completion. Our military wants to acquire capabilities of effective information sharing with Network-Centric Operational Environment(NCOE) for Network-Centric Warfare (NCW). In this paper, we suggested an information broker for overcoming current limits and maximizing future expandability and possibility of information sharing capacities. The information broker, which is an intermediate layer between users and information providers, provides the functions for mediating and managing information and for ensuring security of the system. We evaluated the consistency of proposed architecture and the implementation of the operational architecture design concept using existing design frameworks.

• Journal of the Korean Society of Safety
• /
• v.15 no.4
• /
• pp.139-149
• /
• 2000

This study aims to review and assess the existing postural classification schemes used for evaluating postural loads in industry. The schemes can be classified into three categories: self-report, observational and instrument-based techniques depending upon how to record working postures. Of the three techniques, this study was mainly focused on the observational methods. The observational technique is most widely used in the industrial sites because it does not interfere with work, and is easy and simple to use and cost-effective without requiring the use of expensive equipment for estimating the angular deviation of a body segment from the neutral position. In spite of the usefulness and applicability, the techniques have some problems: 1) The existing observational techniques lack the consistency in the class limits of the motion categories in each body segment; 2) Most of them do not provide the post-analysis criteria needed to judge whether or not any posture is acceptable in view point of the postural load; and 3) They can not precisely evaluate the postural load for a given posture because the external loads and dynamic factors including acceleration, moment and force were not taken into consideration.

• Geomechanics and Engineering
• /
• v.16 no.6
• /
• pp.627-634
• /
• 2018

Soil stabilization is an essential engineering process to enhance the geotechnical properties of soils that are not suitable for construction purposes. This study focuses on using coconut coir, a natural fibre to enhance the soil properties. Lime, an activator is added to the reinforced soil to augment its shear strength and durability. An experimental investigation was conducted to demonstrate the effect of coconut coir fibers and lime on the consistency limits, compaction characteristics, unconfined compressive strength, stress-strain behaviour, subgrade strength and durability of the treated soil. The results of the study illustrate that lime stabilization and coir reinforcement improves the unconfined compressive strength, post peak failure strength, controls crack propagation and boosts the tensile strength of the soil. Coir reinforcement provides addition contact surface, improving the soil-fibre interaction and increasing the interlocking between fibre and soil and thereby improve strength. Optimum performance of soil is observed at 1.25% coir fibre inclusion. Coir being a natural product is prone to degradation and to increase the durability of the coir reinforced soil, lime is used. Lime stabilization favourably amends the geotechnical properties of the coir fibre reinforced soil.

• Journal of KIBIM
• /
• v.10 no.4
• /
• pp.98-109
• /
• 2020

Based on the prior research which developed the consistency review checklist of the BIM model and 2D drawing through the drawing analysis of the construction documents phase, the apparent limits of the existing template and the template development items were derived. As well, the BIM-based drawing templates of the construction documentation phase were developed and verified using ArchiCAD BIM software. The developed template was then applied to the actual project model in the construction documents phase, and, as a result, 50% of existing work elements could be utilized as templates. This is an increase of more than 30% over the existing template utilization elements, and it is analyzed to be effective in practical application and utilization. Based on the results of this study, if the BIM model construction criteria matching the drawing's utilization purpose are presented, while at the same time the BIM data interlocking and drawing template development studies are conducted, the utilization of BIM data can be maximized and additional drawing work can be minimized to increase the percentage of template utilization elements. In addition, it is believed that this can employed to address functional and institutional problems of BIM-based drawing and make a contribution to the activation of BIM.

• Geomechanics and Engineering
• /
• v.29 no.5
• /
• pp.549-565
• /
• 2022

Severe acid rains can be a major source for geotechnical and environmental problems in any soil depending on the acid type and concentration. Hence, this study investigates the individual severe effects of sulfuric, hydrochloric and nitric acids on the geotechnical properties of real field soil through a series of experimental laboratory tests. The laboratory program consists of experimental tests such as consistency, compaction, unconfined compression, pH determination, electrical conductivity, total dissolved salts, total suspended solids, gypsum and carbonates contents. The experimental tests have been performed on the untreated soil and individual acid treated soil for acid concentrations range of 0% to 20% by weight. In addition, a unique hyperbolic mathematical model has been used to predict significant geotechnical characteristics for acid treated soil. The plastic and liquid limits and optimum moisture content have been increased under the effect of all the used acids whereas the maximum dry density and unconfined stress-strain behavior have been decreased with increasing the acid concentrations. Moreover, the used hyperbolic mathematical model has predicted all the geotechnical characteristics very well with a very high coefficient of determination (R²) value and lowest root mean square error (RMSE) estimate.