• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.4
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• pp.89-98
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• 1996

This study was conducted to evaluate the relationships between the geotechnical properties and the CBR values of the subgrade materials used in the rural roal construction. A total of 77 Soil samples was investigated and tested from 45 agricultural and industrial sites in Kyungpook Province. The results obtained are as follows : 1. The maximum dry densities of the coarse grained soils are larger than those of the fine grained soils. The optimum moisture contents of the coarse grained soils are smaller than those of the fine grained scils. 2. The mean values of the medified CBR values of the soils classified by the USCS, are decreased in the order of GP-GM, SW-SM, GM, SC, SP-SM, ML, CL-ML. And, those classified by the AASHTO are decreased in the order of A-i-a, A-i-b, A-2-4, A-3, A-4, A-6, A-7-6. 3. As passing percentage of No.200 sieve is increased, the CBR Value of soils is decreased gradually. 4. As the optimum moisture contents of the soil is increased, the CBR values is decresed the maximum dry density of the soils increased, the CBR values increased. 5. The CBR values are decreased as Group-lndex(GI) are increased. And Activity(A) is showed no relation with the CBR values. 6. The relation ships between the modified CBR value and standand proctor compaction CBR value at 95% compaction ratio can he expressed as the following equation : Y(CERmod)= 2.3638 + 0.8922X(CBR25).

• Journal of Korea Multimedia Society
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• v.5 no.5
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• pp.571-581
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• 2002

Many periodic broadcasting schemes for near VoD systems are proposed. Recently non-uniform segmentation schemes have been used to develop periodic broadcasting techniques for near VoD. These techniques give significant reductions in start-up latency as compared with more conventional uniform segmentation. However, all of these schemes assume that the videos are CBR-encoded. Since a CBR-encoded video has a target average tate than an VBR encoding, there is potential to obtain further Performance Improvements by using VBR videos. Unfortunately, however, the studies concerning broadcasting with VBR video ate rare and the existing techniques have the problem of virtual loss. In this paper, we modify Skyscraper Broadcasting Scheme for broadcasting with VBR videos which is a representative non-uniform segmentation scheme lot CBR videos. A VBR video can be transmitted at constant bit rate (CBR) by using prefetching. With this idea we propose Modified Skyscraper Broadcasting Schemes for VBR videos and make performance evaluation by simulation. We show that our schemes have a better performance than Skyscraper Broadcasting Scheme for CBR videos.

• Journal of the Korean GEO-environmental Society
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• v.3 no.1
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• pp.57-66
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• 2002

Generally, the California Bearing Ratio(CBR) for the material of subgrade is estimated without considering the anti-frost layer into the subgrade layer when pavements are designed. A pavement structure is determined according to the CBR. However, recently the design method taking the anti-frost layer into the subgrade layer is getting prevail. It makes the top of the subgrade layer strengthen and the thickness of the road pavement structure decreased. By the way, some confusion may be caused because theoretically the general equation for the mean CBR to combine the material of the subgrade layer and anti-frost layer have not been developed well. In this paper, laboratory and field CBR tests were performed to estimate of the mean CBR for the subgrade layer including the anti-frost layer. From the basis of the test results, modified equation which is calculating the mean CBR of the subgrade layer has been proposed. Finally, economical efficiency was considered by comparing the pavement thickness with the road pavement design using CBR of the subgrade layer alone and the road pavement design using the mean CBR including the anti-frost layer.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.2
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• pp.149-155
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• 2008

The road construction, as part of effort to ease the worsening traffic, has been underway throughout the nation, while the existing road has been increasingly losing its load carrying capacity due to such factors as heavy traffic and weathering. In the case of site, the soil type, plasticity index, and specific gravity were SC, 12.2%, and 2.66, respectively. The maximum dry density, optimum moisture content and modified CBR were $1.895g/cm^3$ (Modified Compaction D), 13.6%, and 16.2%, respectively. A correlation of coefficient expressed good interrelationship by 0.90 between the CBR estimated from a dynamic penetration index of dynamic cone penetrometer test and a deformation modulus converted from a dynamic deflection modulus obtained from a portable FWD test.

• Journal of the Korea Safety Management & Science
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• v.3 no.4
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• pp.103-112
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• 2001

In Factory, as the number of machine is increased the more maintenance efforts are necessary. Multi maintenance issues may occur at a certain time and the determination of maintenance sequence is needed. In this study, we first compare the priority of machines and the impact value using modified FMEA(Failure Mode Effect and Analysis) method. Also, CBR(Case-based Reasoning) approach is applied to retrieve similar fault cases of current machine problem. The proposed methodology will be useful to implement decision support system of maintenance sequence for CMMS/EAM (Computerized Maintenance Management System/Enterprise Asset Management).

• Journal of the Korean Geotechnical Society
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• v.34 no.12
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• pp.105-113
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• 2018

In this study, the engineering properties including bearing capacity of subgrades stabilized with a binder are analyzed by laboratory and field experiments. The main components of the binder are CaO and $SO_3$. After the binder was mixed with a low plasticity clay, the passing rates were relatively decreased as the sieve mesh size increased. Not only did the soil type change to silty sand, but engineering properties, such as the plasticity index and modified California bearing ratio (CBR), were improved for the subgrade. A comparison of the compaction curves of the stabilized subgrade and field soil compacted with the same energy demonstrated an increase of approximately 6% in the maximum dry unit weight, slight decrease in optimum moisture content, and considerable increase improvement in grain size. In the modified CBR test, the effect of unit weight and strength increase of the modified soil (with a specific amount of binder) was remarkably improved. As the proportion of granulated material increased after the addition of binder, the swelling was reduced by 3.3 times or more during initial compaction and 6.5 times by final compaction. The unconfined compressive strength of the specimens was maintained at the homogeneous value with a constant design strength. The stabilized subgrade was validated by applying it in the field under the same conditions; this test demonstrated that the bearing capacity coefficients at all six sites after one day of compaction exceeded the target value and exhibited good variability.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.11a
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• pp.75-79
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• 2001

near VOU 시스템의 주기적 브로드캐스팅 방식(periodic broadcasting system)으로 여러 가지방법이 제시되었다. 그러나, 대부분 CBR 비디오를 전송하기 위한 방법이다. 요즘의 비디오들은 주고 VHR방식으로 압축되어 있어 VBR 비디오의 브로드캐스팅 기법이 필요하다. 하지만, 이에 대한 연구가 미미한 상태이다. 본 논문에서는 CBR 비디오의 브로드캐스팅 방식의 하나인 SB(Skyscraper Broadcasting)을 수정하여 VBR 비디오를 브로드캐스팅 하는 방법을 제시하였다. 관 논문에서 제시한 방식의 성능 평과 결과, 짧은 초기지연시간과 적은 버퍼가 필요함을 보였다.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2006.06a
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• pp.327-335
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• 2006

Case Based Reasoning (CBR) has come to be considered as an appropriate technique for diagnosis, prognosis and prescription in medicine. However, canventional CBR has a limitation in that it cannot incorporate asymmetric misclassification cast. It assumes that the cast of type1 error and type2 error are the same, so it cannot be modified according ta the error cast of each type. This problem provides major disincentive to apply conventional CBR ta many real world cases that have different casts associated with different types of error. Medical diagnosis is an important example. In this paper we suggest the new knowledge extraction technique called Cast-Sensitive Case Based Reasoning (CSCBR) that can incorporate unequal misclassification cast. The main idea involves a dynamic adaptation of the optimal classification boundary paint and the number of neighbors that minimize the tatol misclassification cast according ta the error casts. Our technique uses a genetic algorithm (GA) for finding these two feature vectors of CSCBR. We apply this new method ta diabetes datasets and compare the results with those of the cast-sensitive methods, C5.0 and CART. The results of this paper shaw that the proposed technique outperforms other methods and overcomes the limitation of conventional CBR.

• Geomechanics and Engineering
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• v.36 no.6
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• pp.619-629
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• 2024

To improve the utilization rate of phosphate tailings (PTs) and widen the sources of subgrade filler, the PTs is employed to modify clay, forming a PTs modified clay, applied in the subgrade. Accordingly, the environmental friendliness of PTs was investigated. Subsequently, an optimal proportion was determined through compaction and California Bearing Ratio (CBR) experiments. Afterward, the stability of mixture with the optimal proportion was further evaluated through the water stability and dry-wet stability experiments. Finally, via the gradation and microstructure experiments, the strength mechanism of PTs modified clay was analyzed. The results show that the PTs were classified in the non-hazardous solid wastes, belonging to Class A building materials. With the increase of PTs content and the decrease of clay content, the optimum water content and the swelling degree gradually decrease, while the maximum dry density and CBR first increase and then decrease, reaching their peak value at 50% PTs content, which is the optimal proportion. The resilient modulus of PTs modified clay at the optimal proportion reaches 110.2 MPa. The water stability coefficient becomes stable after soaking for 4 days, while the dry-wet stability coefficient decreases with the increase of cycles and tends to be stable after 8 cycles. Under the long-term action, the dry-wet change has a greater adverse impact than continuous soaking. The analysis demonstrates that the better strength mainly comes from the skeleton role of PTs and the cementation of clay. The systematic laboratory test results and economic analysis collectively provide data evidence for the advantages of PTs modified clay as a subgrade filler.

• Geomechanics and Engineering
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• v.14 no.6
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• pp.533-544
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• 2018

The importance of using materials cost effectively to enhance the strength and reduce the cost, and weight of earth fill materials in geotechnical engineering led researchers to seek for modifying the soil properties by adding proper additives. Lightweight fill materials made of soil, binder, water, and Expanded polystyrene (EPS) beads are increasingly being used in geotechnical practices. This paper primarily investigates the behavior of sandy soil, modified by EPS particles. Besides, the mechanical properties of blending sand, EPS and the binder material such as fly ash and cement were examined in different mixing ratios using a number of various laboratory studies including the Modified Standard Proctor (MSP) test, the Unconfined Compressive Strength (UCS) test, the California Bearing Ratio (CBR) test and the Direct Shear test (DST). According to the results, an increase of 0.1% of EPS results in a reduction of the density of the mixture for 10%, as well as making the mixture more ductile rather than brittle. Moreover, the compressive strength, CBR value and shear strength parameters of the mixture decreases by an increase of the EPS beads, a trend on the contrary to the increase of cement and fly ash content.