• Journal of the Korean Geosynthetics Society
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• v.3 no.2
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• pp.13-21
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• 2004

This paper deal with the analysis of the causes about case of collapsed reinforced-soil retaining wall. The analysis of the cause was carried through experimentation, slop stability analysis and literature study. The experimentation treated the large direct shear test, the hydraulic conductivity test and the other basic test through backfill extraction from collapsed reinforced-soil retaining wall. The ultimate tensile strength was established by rib tensile strength test of geogrid. The analysis of internal and external stability of reinforced-soil retaining wall was performed on the basis of parameters. The result of analysis, reinforced-soil retaining wall and the slope at the dry season are stable. However, the factors that fine-grained soil at hydrometer test exceed the standard of the design, rainfall duration is too long at the time of collapse and monthly pricipitation is heavy, which are causes of the collapse.

• Journal of Digital Convergence
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• v.12 no.8
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• pp.377-387
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• 2014

The purpose of this study is to suggest improvement ways of outpatient process via a simulation model and to improve operational efficiency. Three experimentation scenarios were implemented into the simulation model to determine which proposed scenario provides better improvement in terms of the following performance measures: LOS(Length of Stay), patient waiting time, patient travel time, and staff utilization. The hospital medical data collection and statistical tools used to analyze the process mining tools. And the PIOS simulation tool was used and the validity of the model was verified by using t-test. The simulation results demonstrated that oupatient process of center type is most efficient. Simulation approach is a powerful technique that supports efficient decision-making compared to traditional healthcare management approach based on past experience, feelings, and intuition. Therefore, the proposed experimentation model has wide applicability in healthcare systems.

• Journal of Korean Academy of Nursing
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• v.30 no.6
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• pp.1521-1530
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• 2000

This descriptive study identifies nursing students' methods of studying related to the learning stages, based on a sample of 251 nursing students in a Korean university. The main findings of the study are as follows. The major learning styles of nursing students were accomodation (68.6%), divergen (53.6%), and convergence (38.8%) for the first, second, third, and fourth year group. For all students, the majority (71.3%) showed accomodation or the divergence. The learning styles for grade level were significantly different, (x2=110.021, df=9, p=0.001). The stage of concrete experience was the majority for all of the first year group (51.8%), the second year group (57.1%), and the third year group (61.3%). But, active experimentation (41.9%) was the majority for the fourth year group. Also there were significant differences between the stages of learning by age (x22= 64.391, df=9, p=0.001). The most significant result of the study was the establishment of different modes of learning stages by year, thus supporting the experiential learning theory. The greatest change of style from the first year group to the second year group was reflective observation (7.3%longrightarrow12.9%). That from the second year group to the third year group was the abstractive conceptualization (14.3%longrightarrow21.3%); and that from the third year group to the fourth year group was active experimentation (12.0%longrightarrow41.9%). This reflects the same cycle as indicated by the experimental learning theory of Kolb. According to the study, nursing students' learning stages tended to be more unbalanced as year increases. Therefore this calls for a careful review of the current nursing curriculum.

• School Mathematics
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• v.6 no.4
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• pp.411-433
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• 2004

Many researchers have reported that 7th graders have severe difficulties in using letters and algebraic expressions. This study investigated the way Microsoft Excel contributes to student's understanding of letters and algebraic expressions. For six hours through two weeks, four 7th grade students experienced various activities with Excel after school and both before and after the experimentation, the interviews to check their understanding was conducted. The results were as follows; First, after the experimentation, students used various letters to express formulas and recognized that letters represent not only some objects but also changing objects. Also they accepted that same objects could be represented by different letters and different objects could be represented by the same letters. Second, Excel improved students' abilities to discriminate variables and invariables in the problem and to find mathematical relationships among variables. And with Excel students could divide the whole calculation procedure into several steps in order to handle it more easily. Also, Excel made immediate numerical feedback possible and it made students express the calculation in a more formalized way than a paper and pencil environment did.

• Geotechnical Engineering
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• v.13 no.3
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• pp.33-52
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• 1997

A three dimensional nonlinear finite element analysis is used to study the influence of various design decisions for tieback walls. The numerical model simulates the soldier piles and the tendon bonded length of the anchors with beam elements, the unbonded tendon with a spring element, the wood lagging with the shell elements, and the soil with solid 3D nonlinear elements. The soil model used is a modified hyperbolic model with unloading hysteresis. The complete sequence of construction is simulated including the excavation, and the placement and stressing of the anchors. The numerical model is calibrated against a full scale instrumented tieback wall at the National Geotechnical Experimentation Site (NGES) on the Riverside Campus of Texas A&M University. Then a parametric study is conducted. The results give information on the influence of the following factors on the wall behavior : location of the first anchor, length of the tendon unbonded zone, magnitude of the anchor forces, embedment of the soldier piles, stiffness of the wood lagging, and of the piles. The implications in design are discussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.666-672
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• 2017

Our research team is developing a 6-DOF manipulator for narrow workspaces in press forming processes, such as placing PEM nuts on the bottom of a chassis. In this paper, kinematic analysis was performed for the position control of the manipulator, along with structural analyses for position accuracy with different payloads. First, the Denavit-Hatenberg (DH) parameters are defined, and then the forward and backward kinematic equations are presented using the DH parameters. The kinematic model was verified by visual simulation using Coppelia Robotics' virtual robot experimentation platform (V-REP). Position accuracy analysis was performed through structural analyses of deflection due to self-weight and deflection under full payload (5 kgf) in fully opened and fully folded states. The maximum generated stress was 22.05 MPa in the link connecting axes 2 and 3, which was confirmed to be structurally safe when considering the materials of the parts.

• Journal of environmental and Sanitary engineering
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• v.16 no.3
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• pp.22-27
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• 2001

It have been investigated how algal and bacterial symbiotic reaction influences on removal of organic carbon in river ecosystem. And artificial experimentation apparatus was made for algae'and bacteia'culture as lab scale. Investigating and researching minutely the change of concentration of organic carbon substrate and the change of population density of algae'and of bacteria'with this artificial experimentation apparatus, the next results could be obtained. 1. Successful decrease of DOC(dissolved organic carbon) could not be expected unless algal and bacterial biomass floe was nut formed effectively and unless biosorption was not proceeded effectively in the very culture system in which artificial synthetic wastewater was supplied continuously at constant rate. 2. In conditions of culture liquid of 1335 glucnse mg/L(type 1) and of 267 glucose mg:L(type 2), the algal dominant species was always Chlorella vulgaris in both types in which artificial synthetic wastewater were supplied continuously at constant rate and algae population density was around maximum 107 cells/mL. 3. It was around 108 ~ 107 cells/mL that the population density of heterotrophic bacterium. In culture medium systems type 1 and type 2 in which artificial wastewater were supplied continuously at constant rate, the same density appeared initially when using the population density of Escherichia coli w 3110 as indirect indicator. And this density decreased rapidly till the culturing date 35 days were passed away, while this density increased with gentle slope after same date and then the trend of change at type 2 was more severe than one at type 1. 4. When seeing such a change of population density of Escherichia coli w 3110, the growth of heterotrophic bacterium appeared as survival instinct pattern of broader requirement of nutrient at condition of low concentration of organic carbon substrate than condition of high concentration of same substrate.

• The Journal of Korean Obstetrics and Gynecology
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• v.19 no.3
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• pp.121-134
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• 2006

Purpose : Cuscuta chinensis Lam. is utilized extensively as important medicines for threatened abortion habitual abortion. However, objective data related to an embryo is not existed until now. Therefore, this study is focused to find out stability of Cuscuta chinensis Lam. about an embryo during pregnancy based on data related to stability of nerve cell and antioxydative effect by using neural cell line, PC 12 cell. Methods : Experimentation concerns cytotoxic effects and antioxydative effect through methods such as MTT ssay, western botting after abstracting an undiluted solution from domestic Cuscuta chinensis Lam. Results : 1. As a result of experimentation on MTT assay according to each magnification from Cuscuta chinensis Lam. extraction solution with different abstraction methods, cytotoxic effect is not observed to all extract except an undiluted solution which is abstracted from MeOH stiring. Also, an undiluted solution in stiring with MeOH could not confirm whether come from Cuscuta chinensis Lam. or not. 2. As a result of revelation of Bax and GSK-3${\beta}$ which is responsive to the first stage from general stress in order to observe antioxydative effects of Cuscuta chinensis Lam. revelation of Bax by Cuscuta chinensis Lam. appeared to decrease. Conclusion : Cytotoxic effects with Cuscuta chinensis Lam. about PC12 cell is not discovered and it assume that it would be anti apoptotic effect by ROS as Bax and GSK-3${\beta}$ inviable effect. In the future, this study could be used as basic data for additional research on Cuscuta chinensis Lam. and effect and stability of complicated prescriptions for keeping pregnancy.

• Geotechnical Engineering
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• v.14 no.6
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• pp.81-92
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• 1998

A beam on elasto-plastic foundation modeling of soldier pile and woodlagging tieback walls or anchored walls was developed and tested. An instrumented full scale tieback wall in sand was constructed at the National Geotechnical Experimentation Bite located on Texas A&M University. The experimental earth pressure deflection relationship (p-y curves) was developed from the measurements. The construction sequence was simulated in the proposed method. The conceptual methodology of an anchored wall design was introduced by using the proposed method. The proposed method was evaluated with the measurements of case histories in sand and clay. A parametric research was performed to study the most influencing factors for the proposed method. It is concluded that the proposed method represents a significant improvement on the prediction of bending moments and deflections of the properly designed walls.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8A
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• pp.575-582
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• 2009

The localization algorithm(LAtu) using the IDentification Code($C_{ID}$) is suggested in RSS(Received Signal Strength) based Wireless Sensor Network(WSN), and the localization system using the suggested algorithm is designed and implemented in this paper. In addition to this, the performance of ranging correction quality and localization error of the localization system(System(LAtu)) that is developed using the LAtu is analyzed and compared with that of the localization system(System(LAieee)) using the channel model of IEEE 802.15.4 standard(LAieee) by the actual experimentation. From the experimentation, the ranging correction quality is analyzed that the LAtu is highly better than the channel model of LAieee about 34% under the distance between the moving module and the beacon module($D_{MM-BM}$) is 2m, and is also a few better than that of the LAieee about average 5% under the $D_{MM-BM}$ is above 5m. The localization error quality of the System(LAtu) is lower than that of the System(LAieee)) about 1cm under the lecture room and 4cm in the large lecture room.