• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.8
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• pp.974-985
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• 2016

Riverbed Modeler, which is a commercial packet-level discrete event simulator is used to model, design, and simulate complicated communication protocols and large-scale network. Riverbed Modeler got credit for its reliability in field of network simulation. In the MANET simulation environment using Riverbed Modeler, it is very complicated to add a new routing protocol into existing architecture of routing protocols because it is required lots of modifications of protocol recognition. In this paper, we propose Routing Adding Framework which can reduce errors or mistakes during modifying the existing routing support architecture. Routing Adding Framework is provided as a adapter API for protocol recognition. and it is only minimum modifications for protocol identifiers when a new routing protocol is added to the child process of manet_mgr process which manages routing protocols for IP layer. With Routing Adding Framework, we can reduce less than half modification. Then, we shows an example of implementation of a hybrid routing protocol AntHocNet using Routing Adding Framework, and we verify its design and application of the Routing Adding Framework by obtaining simulation result with similar result given by AntHocNet.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.6
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• pp.1367-1375
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• 2015

The purpose of this paper is to suggest 10 mm aggregate specification for thin layer asphalt pavement using steel slag. Aggregate gradations of conventional dense-graded asphalt mixtures were made by fuller's model, whereas 10 mm dense-graded asphalt mixture was obtained tender mix due to close to the maximum density line. The proposed aggregate gradation specification was made to have enough VMA and well-interlocking refer to foreign standards. The correlation between the proposed aggregate gradation and the properties of mixtures were analyzed using Gradation Ratio (GR) and Compacted Aggregate Density (CAD). The CAD index has a high $R^2$ of 0.86-0.99 because the CAD index is able to reflect various aggregate properties. As the results of evaluation by CAD index the proposed aggregate gradation provides more reliable stability and VMA. The percent passing (%) of aggregate size smaller than 0.3 mm was limited 10% or more for improving crack resistance. This limitation increased for 15% of the asphalt mixture's toughness.

• The korean journal of orthodontics
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• v.21 no.2 s.34
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• pp.259-272
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• 1991

Orthodontic traction has been suggested as the treatment of choice for intrusive luxation injuries. Prior research has shown orthodontic forces to be ineffective in the presence of ankylosis or in cases with zero mobility following the injury. If orthodontic traction is to be effective, it must be initiated prior to the onset of ankylosis. The purpose of this study was to describe the effects of intrusive luxation at various times following the injury, and to determine the time of the onset of ankylosis, and to examine what effect immediate partial luxation has on the onset of ankylosis. Eight young mongrel dogs were utilized for this study. Intrusive luxation was produced with an axial impact using a gravity hammer and a specially designed holding device on 4 teeth (2 max. and 2 man. first premolars) in each dog. The teeth were intruded approximately 3-4mm in an axial direction. One maxillary and one mandibular premolars were partially luxated with the other two teeth being untouched. Pre and posttrauma tooth position was documented with plaster models and radiographs taken with an individualized X-ray jig. Dogs were sacrificed immediately following the injury and at 1, 2, 4, 7, 10, 14 and 21 days respectively. Tetracycline was administered as a vital bone marker 24 hours before sacrifice. Block sections of the tooth and alveolus were prepared for decalcified and non decalcified histologic sections. The effects of traumatic intrusion were analyzed by means of model casts, radiographs, tetracycline bone marking and histologic preparations. The results obtained were as follows: 1. The animal sacrificed immediately following the injury displayed alveolar fractures, torn periodontal ligaments, and areas of direct tooth-bone contact. 2. The odontoblastic layer of the pulp was disorganized as early as 24 hours after the injury. 3. Bony remodeling was noted at 4 days along with active surface resorption. 4. Ankylosis was first seen 7 days after the injury. 5. Osteogenesis in the dentin (thick tetracycline bands) was observed 7 days after the injury. 6. There was no progressive root resorption and ankylosis where the periodontal ligament has been healed. 7. The Luxated group showed significantly more root resolution and ankylosis than the Nonluxated group with increased observation periods. The results suggest that ankylosis may occur within the first week following the injury, and hence orthodontic traction should be initiated as soon after the injury as possible.

• Journal of the Korean GEO-environmental Society
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• v.2 no.3
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• pp.47-56
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• 2001

In the present study, mainly to determine the embarkation time of equipment in dredged clay fills, an analytical approach is performed to predict a variation of the undrained shear strength in the outermost layer. In this approach, Gibson's non-dimensional linear constant defining the relationship between the void ratio and the effective stress is employed. Also in this approach, void ratios and settlements associated with the volume change due to the self-consolidation and the desiccation shrinkage are evaluated at various elapsed times based on the finite difference solution technique proposed by the authors(1999) and the developed computer program named as DSCON. Predicted results(water content ratio, unit weight and undrained shear strength) are compared with those of laboratory model tests conducted with soil samples obtained from the Koheung site. Based on the predicted undrained shear strengths, possible embarkation time of a equipment is also evaluated. In addition, further analyses are made to indirectly verify the efficiency of the analytical approach proposed in the present study using the PSDDF computer program which can consider the drainage efficiency.

• Journal of the Korean GEO-environmental Society
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• v.10 no.4
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• pp.5-13
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• 2009

The runoff-reducing facilities using infiltration was considered for the sustainable and sound water management. However, for practical utilization, many problems are attended and therefore effort on improvements are required. In this study, methods of improvement for infiltration facilities proposed by Infiltration-Storage System (ISS) and the effect of runoff reduction were analyzed by hydraulic experimental study. In order to analyze the infiltration characteristics of proposed runoff reduction facilities in this study, it was applied to various rainfall condition and surface material considering development and urbanization influences. As a results of hydraulic model experiment, Infiltration-Storage System (ISS) made addition to effect of reduction by lower layer of accumulative infiltration quantities. And then as rainfall-intensity was increased, accumulative infiltration rates were increased in this study. Thus, Infiltration-Storage system (ISS) was more efficient than existing runoff reduction facilities because of increasing infiltration rate. Such a result was guaranteed application of ISS as runoff-reducing facilities. Therefore, ISS is expected to be capable for practical application if subsequent research for improvements are followed. Additionally, results of this study are expected to provide fundamental research data on infiltration facilities.

• Journal of the Korean GEO-environmental Society
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• v.15 no.12
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• pp.109-115
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• 2014

The purpose of this study is to estimate the sediment volume concentration of the liquified-solid mixture which is included fine sediment fractions, according to the variance of the channel slope and the water supply. The numerical model was performed by using the Finite Differential Element Method (FDM) based on the equation for the mass conservation, momentum conservation and the equation of coarse sediment an fine sediment. In comparison of varying the channel slope, the deeper the channel slope, the inflection point of the sediment concentration was occurred rapidly. In comparison of variance of the water supply, as the water supply increases fluctuation with high sediment concentration. In this situation, debris flow changes to the turbulent flow and the sediment becomes to be floated. In comparison varying the length paved saturated sediment, the longer the length, the high concentration of sediment occurred, for the safety of the slope it is needed to check the possibility of the erosion in the slope by debris flow. The results of this study will provide useful information in predicting of the disaster by the liquified-solid mixture and in prevention of the debris flow with various the slope in the mountain side.

• Journal of the Korean Geotechnical Society
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• v.15 no.1
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• pp.99-112
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• 1999

By using 92 values of lateral earth pressure coefficient(K) measured in Korea, the tendency of K with varying depth is analyzed and compared with the range of K defined by Hoek and Brown. The horizontal stress is generally larger than the vertical stress in Korea : About 84 % of K values are above 1. In this study, the theory of elasto-plasticity is applied to analyze the variation of K values, and the results are compared with those of numerical analysis. This reveals that the erosion, sedimentation and weathering of earth crust are important factors in the determination of K values. Surface erosion, large lateral pressure and good rock mass increase the K values, but sedimentation decreases the K values. This study enable us to analyze the effects of geological processes on the K values, especially at shallow depth where underground excavation takes place. A neural network expert system using multi-layer back-propagation algorithm is developed to predict the K values. The neural network model has a correlation coefficient above 0.996 when it is compared with measured data. The comparison with 9 measured data which are not included in the back-propagation learning has shown an average inference error of 20% and the correlation coefficient above 0.95. The expert system developed in this study can be used for reliable determination of K values.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.5
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• pp.1907-1914
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• 2013

Textile-type heat exchangers installed on the tunnel walls for facilitating ground source heat pump systems, so called "energy textile", was installed in an abandoned railroad tunnel around Seocheon, South Korea. To evaluate thermal performance of the energy textile, a series of long-term monitoring was performed by artificially applying daily intermittent cooling and heating loads on the energy textile. In the course of the experimental measurement, the inlet and outlet fluid temperatures of the energy textile, pumping rate, temperature distribution in the ground, and air temperature inside the tunnel were continuously measured. From the long-term monitoring, the heat exchange rate was recorded as in the range of 57.6~143.5 W per one unit of the energy textile during heating operation and 362.3~558.4 W per one unit during cooling operation. In addition, the heat exchange rate of energy textile was highly sensitive to a change in air temperature inside the tunnel. The field measurements were verified by a 3D computational fluid dynamics analysis (FLUENT) with the consideration of air temperature variation inside the tunnel. The verified numerical model was used to evaluate parametrically the effect of drainage layer in the energy textile.

• Journal of Korea Water Resources Association
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• v.40 no.8
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• pp.601-615
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• 2007

A selective withdrawal method has been widely used to control the quality of water released from a stratified reservoir and to improve downstream ecosystem habitats. Recently, several existing reservoir withdrawal facilities have been modified to accommodate multi-level water intake capabilities in order to adapt the impact of long-term discharge of high turbidity flow. The purpose of this study was to assess the effect of selective withdrawal method on the control of downstream turbidity and its impact on water quality in Daecheong Reservoir. A laterally integrated two-dimensional hydrodynamic and eutrophication model, which was calibrated and validated in the previous studies, was applied to simulate the temporal variations of outflow turbidity with various hypothetical selective withdrawal scenarios. In addition, their impacts on the algal growth as well as water quality constituents were analyzed in three different spatial domains of the reservoir The results showed that the costly selective withdrawal method would provide very limited benefits for downstream turbidity control during two years of consecutive simulations for 2004-2005. In particular, an excessive withdrawal from the epilimnion zone for supplying upper layer clean water resulted in movement of turbidity plume that contained high phosphorus concentrations upward photic zone, and in turn increased algal growth in the lacustrine zone.

• Polymer(Korea)
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• v.29 no.3
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• pp.260-265
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• 2005

The initial burst of drug release is an important role in the controlled delivery of drug having hish toxicity and narrow therapeutic ranges. Nanosphere composed of monolayer could not achieve precisely controlled drug release because of the initial burst of drug on surface. In this study, double layered nanosphere was prepared for sustained drug delivery without initial burst. Double layered nanosphere composed of dextran and PLGA was fabricated by using conventional W/O/W double emulsion method. To control surface tension on the outer layer of nanospheres, PVA was used as a surfactant. Release behavior of dextran as model drug was observed as the $3{\times}1$mm wafers formed by compression mould in the deionized water for 7 days. Double layered nanosphere has sustained release behavior, in contast to single layered nanospheres. such as mechanical mixture and dextran nanospheres. Especially, nanosphere containing PVA $0.2\%$ has shown nearly the zero-order release profile. As a result of this study, double layered nanospheres has more sustained release profile of drug without the initial burst and the release behavior of dexoan on tile double layered nanospheres was controlled by the contents of PVA as a surfactant.