• Journal of the Korean Geotechnical Society
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• v.15 no.3
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• pp.161-176
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• 1999

A powerful numerical method that can be used for modeling rock-structure interaction is the Discontinuous Deformation Analysis (D D A) method developed by Shi in 1988. In this method, rock masses are treated as systems of finite and deformable blocks. Large rock mass deformations and block movements are allowed. Although various extensions of the D D A method have been proposed in the literature, the method is not capable of modeling water-block interaction, sequential loading or unloading and rock reinforcement; three features that are needed when modeling surface or underground excavation in fractured rock. This paper presents three new extensions to the D D A method. The extensions consist of hydro-mechanical coupling between rock blocks and steady water flow in fractures, sequential loading or unloading, and rock reinforcement by rockbolts, shotcrete or concrete lining. Examples of application of the D D A method with the new extensions are presented. Simulations of the underground excavation of the \ulcornerUnju Tunnel\ulcorner in Korea were carried out to evaluate the influence of fracture flow, excavation sequence and reinforcement on the tunnel stability. The results of the present study indicate that fracture flow and improper selection of excavation sequence could have a destabilizing effect on the tunnel stability. On the other hand, reinforcement by rockbolts and shotcrete can stabilize the tunnel. It is found that, in general, the D D A program with the three new extensions can now be used as a practical tool in the design of underground structures. In particular, phases of construction (excavation, reinforcement) can now be simulated more realistically.

• Geophysics and Geophysical Exploration
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• v.10 no.4
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• pp.353-360
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• 2007

We practiced fresh water injection test to identify its applibility as a method of seawater intrusion mitigation technique, and monitored the change of borehole fluid conductivity and the behavior of injected fresh water using borehole multichannel electrical conductivity monitoring and well-logging, and DC resistivity and SP monitoring at the surface. Well-logging and multichannel EC monitoring showed the decrease of fluid conductivity due to fresh water injection. We note that such an injection effect lasts more than several month which means the applibility of fresh water injection as a seawater intrusion control technique. Although SP monitoring did not show meaningful results because of weather condition during monitoring and the defects of electrodes due to long operation time, DC resistivity monitoring showed its effectiveness and applicability as a monitoring and assessment techniques of injection test by means of imaging the behavior and the front of fresh water body in terms of the increase of resistivity with reasonable resolution. In conclusion, we note that geophysical techniques can be an effective method of monitoring and evaluation of fresh water injection test, and expect that fresh water injection may be an practical method for the mitigation of seawater intrusion when applied with optimal design of injection well distribution and injection rate based on geophysical evaluation.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.2
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• pp.11-22
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• 2007

This paper is to discuss analytical techniques to estimate demand sizes and volumes that determine optimal locations for multiple facilities for a given services. While demand size estimation is a core part of location modeling to enhance solution quality and practical applicability, the estimation method has been used in limited and restrict parts such as a single population centroid in a given larger census boundary area or small theoretical application experiments(e.s. census track and enumeration district). Therefore, this paper strives to develop an analytical estimation method of demand size that converts area based demand data to point based population weighted centroids. This method is free to spatial boundary units and more robust to estimate accurate demand volumes regardless of geographic boundaries. To improve the estimation accuracy, this paper uses house weighted value to the population centroid calculation process. Then the population weighted centroids are converted to individual demand points on a grid formated surface area. In turn, the population weighted centroids, demand points and network distance measures are operated into location-allocation models to examine their roles to enhance solution quality and applicability of GIS location models. Finally, this paper demonstrates the robustness of the weighted estimation method with the application of location-allocation models.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.30 no.4
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• pp.157-173
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• 2019

Due to the fact that cognitive authority influences an individual's thoughts so that a given information is perceived as appropriate, people evaluate information based on their cognitive authority. The purpose of the present study is to examine the perception of the cognitive authority of online information sources used by college students to carry out their academic tasks, and to determine whether such perceptions affect the quality assessment of information sources, such as webpages, e-journals, and Wikipedia,. Specifically, we measured how cognitive authority, which were formed by the author, the surface, and the content of an information source influenced its accuracy, usefulness, completeness, and expertise. For this purpose, online surveys were conducted with college students, and 172 valid responses were obtained. Findings indicated that all the characteristics that formed the cognitive authority of an information source had significant impacts on its accuracy, usefulness, completeness, and expertise. The study suggests academic implications that confirm the associations between cognitive authority and credibility of information in the context of online information sources. Furthermore, the study provides practical implications that system developers or operators of information sources need to consider diverse factors that affect their cognitive authority to promote users' trust on the information that they deliver.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.2
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• pp.29-35
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• 2017

In this paper, we investigated a manufacturing process of metal micro-wire interconnection on submillimeter diameter catheter. Over the years, flexible electronic researches have focused on flexible plane polymer substrate and micro electrode manufacturing on its surface. However, a curved polymer substrate, such as catheter, is very important for medical application. Among many catheters, importance of submillimeter diameter steerable catheter is increasing to resolve the several limitations of neurosurgery. Steering actuators have been researched for realizing the steerable catheter, but there is no research about practical wiring for driving these actuators. Therefore we developed a new manufacturing process for metal micro-wire interconnection on submillimeter diameter catheter. We designed custom jigs for alignment of the metal micro-wires on the submillimeter diameter catheter. An UV curing system and commercial products were used to reduce the manufacturing time and cost; Au micro-wire, UV curable epoxy, UV lamp, and submillimeter diameter catheter. The assembled catheter was characterized by using an optical microscope, a resistance meter, and a universal testing machine.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.1
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• pp.23-32
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• 2008

In order to discern the development of technology in creating, properly managing, and characterizing the types used in facade greening, this article examines the instances of facade greening of Bulgaria, Greece and Turkey which is not only located in the latitude similar to South Korea's but also influenced by the both continental and oceanic climate. The study was carried out for 11 months from October 2002 to September 2003. The total 242 places were researched and they were 83 sites in Athens, 77 sites in Istanbul, and 82 sites in Sofia. Varieties, usage, configuration, foundation and characteristics of plants were studied. The goals of greening, and building's surface roughness and thickness, direction of the wall were also researched. The result of survey are as follows; 17 families and 33 species of climbing plants were found in Athens, Istanbul, and Sofia. Thickness of facade greening in the three cities is 46cm in Athens, 39cm in Istanbul, and 53cm in Sofia. The possible facade greening size per a climbing plant, Parthenocissus tricupidata takes up the largest portion of the wall in the three cities similarly followed by Vitis vinifera and Wistaria spp. By its diversity it can be assumed that these plants are most practical for large scale of facade greening and full covering. Evergreen climbing plants such as Hedera helix and Ficus niponica are useful plants for relatively large scale of facade greening area. In the facade greening types, the climbing type is the most dominant in the three cities and most of the climbing type was planted on the natural foundation but the hanging and combination types were planted on an artificial foundation located on the balcony or on the roof of the building. In the directions of the walls for facade greening, the west direction are most popular which is for the improvement of sun shading in summer season. In Sofia the apartments were most applied with facade greening but In Istanbul and Athens the residential buildings and the public buildings were adapted with facade greening actively as well as residential building. The purpose of lowering summer heat took up the highest portion followed by the purpose of ornamentation and maintaining privacy in all surveyed cities.

• Journal of Embryo Transfer
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• v.30 no.3
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• pp.161-170
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• 2015

These studies were conducted to establish the practical Hanwoo (Korean native cattle) improvement system through the combining of embryo transfer technology and confirming individual Hanwoo oocyte culture system and to investigate that correlation of Hanwoo carcass classification (intramuscular marbling) and oocyte donor for blastocyst production in vitro. In case of Hanwoo, the carcass meat quality grades were divided to grade $1^{{+}{+}}$, $1^{+}$, 1, 2, and 3 depends on fat distribution of longest muscle cross-sectional surface. As results, the numbers of follicular oocytes collected from individual fundamentally-registered Hanwoo yielded $1^{{+}{+}}$, $1^{+}$, 1, 2 and 3 meat quality were 9.5, 9.4, 8.5, 8.8 and 8.8 per ovary, respectively. The numbers of retrieval oocyte from follicles were significantly higher in the cattle yield $1^{{+}{+}}$, $1^{+}$ meat quality than in the cattle yield 1, 2 and 3 meat quality (p<0.05). The rates of blastocyst formation were 18.2, 21.3, 29.4, 30.9, and 31.5% in the cattle yield $1^{{+}{+}}$, $1^{+}$, 1, 2 and 3 meat quality of after in vitro maturation, respectively. It was significantly lower in the cattle yield $^{{+}{+}}$ and $1^{+}$ meat quality than in the cattle yield 1, 2 and 3 meat quality (p<0.05). In order to evaluate embryos quality, TUNNEL assay was conducted for each meat quality grade using blastocyst stage embryo on day 8. The results showed that apoptosis cell number was higher tendency in the cattle yield $1^{{+}{+}}$and $1^{+}$ meat quality (81 and 79, respectively) than in the cattle yield 1, 2 and 3 meat quality (51, 48 and 50, respectively) but there was no statistical significance in each group. After embryo transfer, the conception rate of recipient was 53.5 (23 out of 43), 52.1 (38 out of 73) and 58.0% (58 out of 100) in the meat quality of 1, $1^{+}$ and $1^{{+}{+}}$, respectively. These results showed that the conception rate was significantly higher in the cattle yield 1 meat quality than in the cattle yield $1^{{+}{+}}$, $1^{+}$, 2, and 3 meat quality (p<0.05). In summary, these results indicate that the application of confirming Hanwoo individual oocyte culture system and embryo transfer technology can make good use of the genetic resources conservation and improvement of Hanwoo. Relevance of the meat quality grade and reproductive ability of carcasses of Hanwoo will be considered to be one of the effective means for the associated research with obesity and reproduction.

• Korean Journal of Applied Biomechanics
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• v.24 no.2
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• pp.139-149
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• 2014

The purpose of this study was to evaluate the effect of angle change of forefoot's adhesive outsole on the electromyographic activity (EMG) of the erector spinae and selected lower limbs muscle during downhill walking over $-20^{\circ}$ ramp. Thirteen male university students (age: $25.4{\pm}3.9$ yrs, height: $176.2{\pm}5.1$ cm, weight: $717.4{\pm}105.0$ N) who have no musculoskeletal disorder were recruited as the subjects. To assess the myoelectric activities of selected muscles, six of surface EMG electrodes with on-site pre-amplification circuitry were attached to erector spinae (ES), rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), lateral gastrocnemius (LG), and medial gastrocnemius (MG). To obtain maximum EMG levels of the selected muscles for normalization, five maximum effort isometric contraction were performed before the experimental trials. Each subject walked over $0^{\circ}$ and $20^{\circ}$ ramp with three different forefeet's EVA outsole (0, 10, $20^{\circ}$) in random order at a speed of $1.2{\pm}0.1$ m/s. For each trial being analyzed, five critical instants and four phases were identified from the recording. The results of this study showed that the average muscle activities of MG and LG decreased in $20^{\circ}$ shoes compared to $0^{\circ}$ and $10^{\circ}$ ones in the initial double limb stance (IDLS). In initial single limb stance (ISLS) phase, the average muscle activities of ES increased with the angle of forefoot's adhesive outsole, indicating that the increment of shoes' angle induce upper body to flex anteriorly in order to maintain balance of trunk. In terminal double limb stance (TDLS) phase, average muscle activities of TA significantly increased in $20^{\circ}$ outsole compared to $0^{\circ}$ and $10^{\circ}$ ones. There was no external forces acting on the right foot other than the gravity during terminal single limb stance (TSLS) phase, all muscles maintained moderate levels of activity.

• Archives of Plastic Surgery
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• v.38 no.5
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• pp.695-698
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• 2011

Purpose: Since spinal tuberculosis is increasing in prevalence, it appears that a repair of spinal soft tissue defect as a complication of spinal tuberculosis can be a meaningful work. We report this convenient and practical reconstructive surgery which use bilateral latissimus dorsi musculocutaneous advancement flap. Methods: Before the operation, $13{\times}9.5$ cm sized skin and soft tissue defect was located on the dorsal part of a patient from T11 to L3. And dura was exposed on L2. Under the general endotrachel anesthesia, the patient was placed in prone position. After massive saline irrigation, dissection of the bilateral latissimus dorsi musculocutaneous flaps was begun just upper to the paraspinous muscles (at T11 level) by seperating the paraspinous muscles from overlying latissimus dorsi muscles. The plane between the paraspinous muscles fascia and the posterior edge of the latissimus dorsi muscle was ill-defined in the area of deformity, but it could be identified to find attachment of thoracolumbar fascia. The seperation between latissimus dorsi and external oblique muscle was identified, and submuscular plane of dissection was developed between the two muscles. The detachment from thoracolumbar fascia was done. These dissections was facilitated to advance the flap. The posterior perforating vasculature of the latissimus dorsi muscle was divided when encountered approximately 6 cm lateral to midline. Seperating the origin of the latissimus dorsi muscle from rib was done. The dissection was continued on the deep surface of the latissimus dorsi muscle until bilateral latissimus dorsi musculocutaneous flaps were enough to advance for closure. Once this dissection was completely bilateraly, the bipedicled erector spinae muscle was advanced to the midline and was repaired 3-0 nylon to cover the exposed vertebrae. And two musculocutaneous units were advanced to the midline for closure. Three 400 cc hemovacs were inserted beneath bilateral latissimus dorsi musculocutaneous flaps and above exposed vertebra. The flap was sutured with 3-0 & 4-0 nylon & 4-0 vicryl. Results: The patient was kept in prone and lateral position. Suture site was stitched out on POD14 without wound dehiscence. According to observative findings, suture site was stable on POD55 without wound problem. Conclusion: Bilateral latissimus dorsi musculocutaneous advancement flap was one of the useful methods in repairing of large spinal soft tissue defect resulting from spinal tuberculosis.

• Fire Science and Engineering
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• v.23 no.6
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• pp.66-74
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• 2009

When a fire occurs, the concrete structure's strength decreases by the increasing temperature under the fire in certain condition of constant load. And, the ratio of the axial force is changed by such decreased strength so that the structure is deformed. In this research, considering such case, we have conducted an actual fire test for the concrete lining with constant loading condition and various fire conditions. The specimen adopts the shape condition for small practical specimen defined by the EFNARC and we used 24MPa, 40MPa and 50MPa to analyze the thermal properties by the strength. The ratio of loading is imposed by a certain loading condition based on 20% and 40% of the sectional stress in concrete and MHC Fire is selected to realize the thermal impact of the concrete by rapid increasing temperature. As the result of the experiment, in the same ratio of loading, the 50MPa specimen shows more cracks and spalling as time goes on. The area damaged by the fire, according to the functional criteria of the concrete lining under the fire in ITA, does not satisfy with the standard in lack of 50mm depth from the heating surface at total 200mm lining.