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A Study on Dynamic Analyses of Cut and Cover Tunnel during Earthquakes (개착터널에 대한 지진 시 동적수치해석에 관한 연구)

  • Park, Sung-Sik;Moon, Hong-Duk;Park, Si-Hyun
    • The Journal of Engineering Geology
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    • v.25 no.2
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    • pp.237-250
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    • 2015
  • Underground structures such as a tunnel have been considered as safer than structures on the ground during earthquake. However, severe damages of underground structures occurred at subway tunnel during 1995 Kobe Earthquake and such damages are gradually increased. In this study, a dynamic behavior of a cut and cover tunnel surrounded by weathered soils is investigated using Mohr-Coulomb Model. Parametric study was carried out for boundary conditions, tensile strength, and earthquake magnitudes. The results of numerical analyses in terms of ground deformations and stresses acting on the lining were quite dependent on the side boundary condition (free or fix conditions) and tensile strength of surrounding soils. The ground was deformed upward at the end of earthquake when the side boundary condition was fixed, whereas residual deformations were not predicted when it was free. When the tensile strength of a soil was set to the same as its cohesion, residual deformation was less than 1cm, regardless of side boundary conditions or input accelerations. In addition to that, stress conditions at the maximum deformation and end of earthquake were within an allowable range and considered as safe. Proper boundary conditions and material properties such as tensile strength are quite important because they may significantly impact on the results of dynamic analyses.

Development Length of GFRP Rebars Based on Pullout Test (인발실험에 의한 GFRP 보강근의 정착길이 제안)

  • Choi, Dong-Uk;Ha, Sang-Su;Lee, Chang-Ho
    • Journal of the Korea Concrete Institute
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    • v.19 no.3
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    • pp.323-331
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    • 2007
  • The development length equations of the GFRP rebars are suggested based on the pullout tests performed in this study. A total of 48 pullout and modified pullout tests were completed. Test variables included embedment length (L=10, 15, 20, and $30d_b$), vertical and horizontal installation of the rebars, height of the rebars (H=100 and 300 mm), and cover thickness $(C=2{\sim}5d_b)$. D13 GFRP rebars domestically developed were used in the experimental program. The average of the bond strength of all vertically installed GFRP rebars was 6.39 MPa with a 5% fractile of 4.63 MPa. A basic development length equation was derived that resulted in an equation equivalent to the one proposed in the ACI 440.1R-03. Careful reevaluation of the bond strength using the modified pullout test indicated that a modification of the design equation was necessary so that the basic development length increases by 11%. The top bar effect of the horizontally installed rebars as well as the effect of the cover thickness were determined and included in the set of suggested equations. Since the current equations were derived from testing rebars embedded in relatively low strength concrete $(f_{ck}=20{\sim}24MPa)$, they result in conservative development lengths when applied to bars embedded in higher strength concretes.

A Content Analysis of the Trends in Vision Research With Focus on Visual Search, Eye Movement, and Eye Track

  • Rhie, Ye Lim;Lim, Ji Hyoun;Yun, Myung Hwan
    • Journal of the Ergonomics Society of Korea
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    • v.33 no.1
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    • pp.69-76
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    • 2014
  • Objective: This study aims to present literature providing researchers with insights on specific fields of research and highlighting the major issues in the research topics. A systematic review is suggested using content analysis on literatures regarding "visual search", "eye movement", and "eye track". Background: Literature review can be classified as "narrative" or "systematic" depending on its approach in structuring the content of the research. Narrative review is a traditional approach that describes the current state of a study field and discusses relevant topics. However, since literatures on specific area cover a broad range, reviewers inherently give subjective weight on specific issues. On the contrary, systematic review applies explicit structured methodology to observe the study trends quantitatively. Method: We collected meta-data of journal papers using three search keywords: visual search, eye movement, and eye track. The collected information contains an unstructured data set including many natural languages which compose titles and abstracts, while the keyword of the journal paper is the only structured one. Based on the collected terms, seven categories were evaluated by inductive categorization and quantitative analysis from the chronological trend of the research area. Results: Unstructured information contains heavier content on "stimuli" and "condition" categories as compared with structured information. Studies on visual search cover a wide range of cognitive area whereas studies on eye movement and eye track are closely related to the physiological aspect. In addition, experimental studies show an increasing trend as opposed to the theoretical studies. Conclusion: By systematic review, we could quantitatively identify the characteristic of the research keyword which presented specific research topics. We also found out that the structured information was more suitable to observe the aim of the research. Chronological analysis on the structured keyword data showed that studies on "physical eye movement" and "cognitive process" were jointly studied in increasing fashion. Application: While conventional narrative literature reviews were largely dependent on authors' instinct, quantitative approach enabled more objective and macroscopic views. Moreover, the characteristics of information type were specified by comparing unstructured and structured information. Systematic literature review also could be used to support the authors' instinct in narrative literature reviews.

Sensitivity Analysis for Railway Development Areas Using Land Cover Map (토지피복지도를 활용한 철도개발지의 민감도 분석)

  • Kim, Min-Kyeong;Kim, Dong-Yoeb
    • Journal of the Korean Society for Railway
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    • v.20 no.1
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    • pp.76-84
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    • 2017
  • Recently, the 'Ecological Network Restoration Project at Chupungnyeong' has been placed; this project is located at the center of the Baekdu mountain spine, the core of the ecological network of the Korean Peninsula. In the process of industrialization since the early 1900s, this area has been under railroad and road construction; as such, wildlife movements have been interrupted and many cases of road-kill have been found. The investment in railroads has increased because railroads are an environmentally sound means of transportation. Single track railways have been converted to double track electric railways and track reforming projects are underway in order to speed up the current railway system. This study suggests to take land use as a standard for assessing the ecological weaknesses of the domestic geo-spaces that are to be affected by rapid extension of railway lines. The land cover map issued by the Ministry of Environment was overlapped with the Korean Railway Line Map for analysis. The results showed that five items were high in sensitivity: paddy fields, fields, deciduous forests, bare land, and inland waters. It seems to be necessary to set weights for highly sensitive land use types; also, specific evaluation criteria need to be reestablished.

A Study about Current Putting on a Shroud (현행(現行) 수의(壽衣) 착의법(着衣法) 관(關) 연구(硏究))

  • Nam, Min-Ye;Baik, Young-Ja
    • Journal of Fashion Business
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    • v.3 no.2
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    • pp.85-90
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    • 1999
  • A shroud is clothes for giving a dead person a bath and being finely dressed:though our routine clothes have been western, putting on a shroud has been kept comparatively well as a tradition of a conventional ceremony garments. This study is about the current using of dressing a shroud, and for presenting foundations of a way about dressing a shroud in order to make the most of this by everyone, therefore this research will be worthwhile to preserve the traditional custom of giving a dead person a bath and being finely dressed. 1. We must confirm the death of a person before we do Su-Si for controlling rightly a corse. Su-Si is ways of changing a clean clothes after bathing the dead person, tieing up hands, feet and ankles with a string, filling up a mouth, a nose and ears with a wad of cotton, laying down the dead person with his head toward east, and setting up a screen after covering the dead person with a bed sheet. 2. Here are processes of putting on a shroud. After the day of death, first of all, you must untie the string to control rightly a corpse, take off the clothes, and give a dead man a bath. You trim the dead person's fingernails and toenails, put them in O-nang, then put his hands and feet in five pouches, finally put feet in korean socks and wrap with Ak-su. You put a underwear in a overwear in order to put on the clothes easily, and then put on an upper garments after putting on trousers. And put on Sb-sin After you wash the dead person's face and his hair, you put gems and raw rice in his mouth, wrap head with cotton fabrics, and put hairs into five pouches, then put on a headgear which is filled with five pouches. 3. You tie up with hem cloth the dead person dressed a shroud after wrapping with Dae-ryum-km and So-ryumkm. 4. After you encoffin the dead person, you weave coffin strings with cotton fabrics in order to lift up the coffin easily, and lay down a red fabrics having white letters about the dead person's name or social position onto the coffin, then cover the coffin with a coffin cover : finally you leave the coffin at the former place and set up screen.

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Study on Prediction of Performance with Design Variables of Solar-Assisted Still Using Waste Heat from Diesel Generator (디젤 발전기 폐열을 활용한 태양열원 해수담수기의 설계변수에 따른 성능 예측에 관한 연구)

  • Jang, Hyun;Yi, Chung Seob;Suh, Jeong Se;Jeong, Kyoung Yul;Park, Change Dae
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.37 no.12
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    • pp.1061-1068
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    • 2013
  • This study predicts distillate productions according to design variables by numerical analysis when the waste heat from a diesel generator is added to the solar-assisted still proposed in a previous study. Mathematical models were set up in reference to previous studies, and the amount of heat exchange from the waste heat recovery pipe was considered. To ensure the reliability of numerical analysis, the result was compared with that of a previous study and then, the distillate productions according to design variables were obtained by the analysis model. The results were found to generally be in agreement, and the increasing amount of distillate production of the still with the added waste heat was confirmed. In addition, the optimal value of the tilt angle of glass cover and the number of cells were determined by numerical analysis.

A Study of Ways of Paying Insurance Benefits and the Range of Insurance Coverage of Health Insurance for Packed Herbal Medicine (첩약의 건강보험 급여형태 및 급여범위에 대한 연구)

  • Kim, Yong-Ho;Son, Chi-Hyoung;Moon, Ok-Ryun;Kim, Su-Young;Lim, Sabina
    • The Journal of Korean Medicine
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    • v.28 no.3 s.71
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    • pp.244-260
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    • 2007
  • Objectives : The purpose of this study was to provide lawmakers with basic data for the purpose of establishing a policy on health insurance for packed herbal medicine. Methods : To properly execute an insurance system for packed herbal medicine, we surveyed the following questions from May 1st to June 15th, 2006: (1)the way to pay the insurance benefits (2)specific impression (disease) names as related to insurance (3)the range of insurance coverage. We obtained answers from 304 Korea traditional doctors. Results : 89.4% respondents were agreed on execution of health insurance for packed herbal medicine. 93.86% respondents answered that the way to pay insurance benefits and the range of insurance coverage have to be changed properly. Most respondents answered that the coverage should be based on a specific disease being treated, not the current symptoms method which relates to the prescription. The execution of health insurance for packed herbal medicine is expected to increase the number of patients and make the Korean medical system more popular. Conclusion : The findings are expected to make it easier for the general public to get treatment by providing basic data with policy makers that will cover packed herbal medicine in insurance. Also, a proper Korea traditional health insurance program should be set up as soon as possible to widen the choice of medicine for the general public.

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Analysis of Treatment Efficiency according to Open-water in Constructed Wetland (인공습지 내 개방수역 조성에 따른 처리효율분석)

  • Kim, Hyung-Chul;Yoon, Chun-Gyeong;Um, Han-Yong;Kim, Hyung-Jung;Haam, Jong-Hwa
    • Journal of Korean Society on Water Environment
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    • v.24 no.6
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    • pp.709-717
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    • 2008
  • The field scale experiment which is constructed with four sets (0.88 ha for each set) of wetland (0.8 ha) and pond (0.08 ha) systems was performed to examine the effect of plant coverage on the constructed wetland performance and to recommend the optimum development and management of macrophyte communities. After six growing seasons of wetlands, plant coverage was about 100%. And the concentration of DO showed low value (1.0~5.4 mg/L). This is caused by a blighted plant consumed dissolved oxygen with decay in water column. As the result, water column went to be anaerobic conditions and T-N removal rate are 58~67%. Dead vegetation increased nitrogen removal during winter because it is a source of organic carbon which is an essential parameter in denitrification. However, wetland released phosphorus caused by a blighted plant and accumulation, the removal rate of phosphorus might be decreased. To rise of DO concentration, the three open-waters were constructed in cell 3 and 4. Cell 3 has two open-waters (width 10 m, depth 1.8 m) and cell 4 has one open-water (width 20 m, depth 1.8 m). As the result, DO concentration and treatment efficiency of nutrient and BOD were improved. In case that constructed wetland is operated for a long time, physical circulation structure such as open water help continuous circulation of aerobic and anaerobic conditions. Through the constructed open-water, treatment efficiency of phosphorus and nitrogen in wetland could be improved effectively.

Sediment Erosion and Transport Experiments in Laboratory using Artificial Rainfall Simulator

  • Regmi, Ram Krishna;Jung, Kwansue;Nakagawa, Hajime;Kang, Jaewon;Lee, Giha
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.4
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    • pp.13-27
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    • 2014
  • Catchments soil erosion, one of the most serious problems in the mountainous environment of the world, consists of a complex phenomenon involving the detachment of individual soil particles from the soil mass and their transport, storage and overland flow of rainfall, and infiltration. Sediment size distribution during erosion processes appear to depend on many factors such as rainfall characteristics, vegetation cover, hydraulic flow, soil properties and slope. This study involved laboratory flume experiments carried out under simulated rainfall in a 3.0 m long ${\times}$ 0.8 m wide ${\times}$ 0.7 m deep flume, set at $17^{\circ}$ slope. Five experimental cases, consisting of twelve experiments using three different sediments with two different rainfall conditions, are reported. The experiments consisted of detailed observations of particle size distribution of the out-flow sediment. Sediment water mixture out-flow hydrograph and sediment mass out-flow rate over time, moisture profiles at different points within the soil domain, and seepage outflow were also reported. Moisture profiles, seepage outflow, and movement of overland flow were clearly found to be controlled by water retention function and hydraulic function of the soil. The difference of grain size distribution of original soil bed and the out-flow sediment was found to be insignificant in the cases of uniform sediment used experiments. However, in the cases of non-uniform sediment used experiments the outflow sediment was found to be coarser than the original soil domain. The results indicated that the sediment transport mechanism is the combination of particle segregation, suspension/saltation and rolling along the travel distance.

How to Improve Eating Behaviour during Early Childhood

  • Green, Robin John;Samy, Gamal;Miqdady, Mohamad Saleh;Salah, Mohamed;Sleiman, Rola;Abdelrahman, Hatim Mohamed Ahmed;Al Haddad, Fatima;Reda, Mona M.;Lewis, Humphrey;Ekanem, Emmanuel E.;Vandenplas, Yvan
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.18 no.1
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    • pp.1-9
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    • 2015
  • Eating behaviour disorder during early childhood is a common pediatric problem. Many terminologies have been used interchangeably to describe this condition, hindering implementation of therapy and confusing a common problem. The definition suggests an eating behaviour which has consequences for family harmony and growth. The recent Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition does not cover the entire spectrum seen by pediatricians. Publications are substantive but level of evidence is most of the time low. This purpose of this review is to clarify terminology of eating behaviour problems during early childhood; including benign picky eating, limited diets, sensory food aversion, selective eating, food avoidance emotional disorder, pervasive refusal syndrome, tactile defensiveness, functional dysphagia, neophobia and toddler anorexia. This tool is proposed only to ease the clinical management for child care providers. Diagnostic criteria are set and management tools are suggested. The role of dietary counselling and, where necessary, behavioural therapy is clarified. It is hoped that the condition will make its way into mainstream pediatrics to allow these children, and their families, to receive the help they deserve.