• The Journal of the Korea Contents Association
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• v.19 no.2
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• pp.516-524
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• 2019

The purpose of this study is to analyze the cases related to the multi-dimensional urban planning and its related systems that can contribute to the urban regeneration as the policies and projects for stereoscopic city increase. Through the case analysis, urban regeneration function and role of multi-dimensional urban planning are identified as connection of places, activation of local economy, expansion of infrastructure and supply of housing. In the institutional sector, private participation is hindered due to the ban on the establishment of the right to hold state property. In addition, it is difficult to utilize the three-dimensional urban space without land securing at a certain rate based on uniform installation standards of the two-dimensional land use plan, and the problem of insufficient interconnection between law and institution is derived. In conclusion, it should actively support and promote the promotion of the three-dimensional facility with the aim of diversifying the regional infrastructure structure and strengthening the urban function. In addition, development of stereoscopic and compound development should be promoted for old urban areas, and parking lots, underground shopping malls, parking lots, etc. should be installed using the subspaces of parks, schools, roads and traditional markets of old residential areas. Finally, cooperation between the central government, the municipalities and the private sector is necessary for the realization of these urban regeneration projects.

• Tunnel and Underground Space
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• v.28 no.6
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• pp.609-619
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• 2018

This study was carried out at a local limestone mine to analyze the ventilation efficiency of the shaft equipped with a main fan. The results show that its ventilation efficiency is clearly verified for the natural as well as the mechanical ventilation. The airflow rate of $11.7m^3/s$ was induced by the natural ventilation force and the maximum quantity is almost same as the airflow rate estimated by monitoring the average temperatures in the upcast and downcast air columns. Meanwhile, the airflow rate exhausted by the main fan through the shaft was $20.3{\sim}24.8m^3/s$; variation of the quantity was caused by the upward shift of the mine ventilation characteristic curve due to the frequent movement of the equipment. This indicates efforts are required to reduce the ventilation resistance and raise the quantity supplied by the main fan. The turbulent diffusion coefficients along the 1912 m long airway from the portal to the shaft bottom was estimated to be $15m^2/s$ and $18m^2/s$. Since these higher coefficients imply that contaminants will be dispersed at a faster velocity than the airflow, prompt exhaust method should be planned for the effective air quality control. The ventilation shaft and main fan are definitely what local limestone mines inevitably need for better working environment and sustainable development.

• Journal of the Korean Geosynthetics Society
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• v.18 no.1
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• pp.91-101
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• 2019

Recently, small-scale excavation like ground cavity restoration and buried pipe replacement works are being carried out in urban area, in order to improve living convenience. This paper describes experiment results on the ground reinforcement method that can reduce the buried pipe damage, when the differential settlement occurred due to poor compaction of ground below the buried pipe. Plate load tests were conducted to evaluate a reinforcement effect of ground using concrete mat and expansion mat in the ground below the buried pipe. The results showed that the stress reduction ratio by concrete mat and expansion mat according to the surcharge load was about 46%~48% and 39%~42%, respectively. Therefore, the differential settlement of the buried pipe and the ground deformation below the buried pipes were reduced by the reinforcement effect of the concrete mat and expansion mat. This means that it is possible to prevent a buried pipe damage due to underground cavity and ground subsidence, if concrete mat and expansion mat are reinforced in the ground below the buried pipe or on the ground between the buried pipes.

• Geomechanics and Engineering
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• v.24 no.3
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• pp.215-226
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• 2021

To study the evolution mechanism of cracks in rocks with multiple defects, rock-like samples with multiple defects, such as strip-shaped through-going cracks and cavity groups, are used, and the crack propagation law and changes in AE (acoustic emission) and strain of cavity groups under different inclination angles are studied. According to the test results, an increase in the cavity group inclination angle can facilitate the initial damage degree of the rock and weaken the crack initiation stress; the initial crack initiation direction is approximately 90°, and the extension angle is approximately 75~90° from the strip-shaped through-going cracks; thus, the relationship between crack development and cavity group initiation strengthens. The specific performance is as follows: when the initiation angle is 30°, the cracks between the cavities in the cavity group develop relatively independently along the parallel direction of the external load; when the angle is 75°, the cracks between the cavities in the cavity group can interpenetrate, and slip can occur along the inclination of the cavity group under the action of the shear mechanism rupture. With the increase in the inclination angle of the cavity group, the AE energy fluctuation frequency at the peak stress increases, and the stress drop is obvious. The larger the cavity group inclination angle is, the more obvious the energy accumulation and the more severe the rock damage; when the cavity group angle is 30° or 75°, the peak strain of the local area below the strip-shaped through-going fracture plane is approximately three times that when the cavity group angle is 45° and 60°, indicating that cracks are easily generated in the local area monitored by the strain gauge at this angle, and the further development of the cracks weakens the strength of the rock, thereby increasing the probability of major engineering quality damage. The research results will have important reference value for hazard prevention in underground engineering projects through rock with natural and artificial defects, including tunnels and air-raid shelters.

• Tunnel and Underground Space
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• v.33 no.6
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• pp.435-444
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• 2023

In the licensing application for the deep geological disposal system of high-level radioactive waste in Finland, the disposal tunnel backfilling has been changed from the block/pellet (for the construction) to the granular type (for the operation). Accordingly, for establishing the design concept for backfilling, it is necessary to examine applicability to the domestic facility through analyzing problems of the existing method and improvements in the alternative design. In this paper, we first reviewed the principal studies conducted for changing the backfill method in the licensing process of the Finnish facility, and identified the expected problems in applying the block/pellet backfill method. In addition, we derived the evaluation factors to be considered in terms of technical and operational aspects for the backfilling solution, and then conducted a comparative analysis for two types of backfill methods. This analysis confirmed the overall superiority of the design change. It is expected that these results could be utilized as the technical basis for deriving the optimum design plan in development process of the Korean-specific deep disposal facility. However, applicability should be reviewed in advance based on the latest technical data for the detailed evaluation factors that must be considered for selecting the backfilling method.

• Horticultural Science & Technology
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• v.33 no.2
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• pp.166-176
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• 2015

Research was initiated to investigate root growth characteristics of major cool-season grasses (CSG) and to collect basic information useful for sports turf design, construction and maintenance. Several turfgrasses were evaluated in the USGA (United States Golf Association) soil system. Turfgrass entries were comprised 3 blends and 3 mixtures of Kentucky bluegrass (KB, Poa pratensis L.), perennial ryegrass (PR, Lolium perenne L.), and tall fescue (TF, Festuca arundinacea Schreb.). Significant differences were found in root growth, rooting potential and rooting development. These characteristics increased with time after seeding, but varied with establishment stages. In early stage, root length was highest with PR, intermediate with TF and lowest with KB. Evaluation in a middle stage indicated that root growth was similar to early-stage evaluation, but decreased by 13 to 31% compared with early-stage values. Root growth of late stage increased by 34 to 85% over middle-stage root growth. Overall, thhere was not much difference in root length among treatments, with all except Mixture I reaching 22cm in root length. Rooting potential ranking was variable with establishment stage, being PR > KB > TF in early stage, PR > TF > KB in middle stage and TF > PR > KB in late stage. At the end of the study, TF was rated best for rooting development, followed by PR and finally KB. Our results showed that TF was the best species in regard to overall rooting characteristics. TF exhibited excellent rooting development with time after establishment. Bunch-type PR showed fast root growth in the early stage, but rooting quality characteristics decreased with time, especially for rooting development. By contrast, rhizomatous-type KB was poor in early-stage root growth, but rooting characteristics improved with time after establishment. These variations in rooting characteristics among CSGs were considered to arise from differences in establishment vigor, growth habit and genetic characteristics. Information on root growth, rooting potential and rooting development by establishment stages will be useful for sports turf design, construction and maintenance.

• The Journal of Korean Physical Therapy
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• v.3 no.1
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• pp.9-37
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• 1991

The purpose of this . study is to examine the unsatisfactory factors of the physical therapists and to obtain the materials necessary to comply with these factors by analysing their service performance and job satisfaction, To accomplish these purposes, this study was carried out by using the questionnaires 206 physical therapists registered in the Korean Physical Therapists Association, for 35 days from January 7 to February 10, 1990. The result of this study is summarized as follows. 1. Of total respondents, the male accounted for 54.4 percent, while the female for 45.6 percent. Their age showed that 20s accounted for 65.0 percent, while the service period less than 3 years accounted for 66.5 percent. In addition, 63.6 percent of them served at the general clinics. 2. The general clinics caused the physical therapists to serve for 10 hours or more per day, where their therapy room located in the underground accounted for 41.3 percent. Their health diagnosis status indicated that nondiagnosis accounted for 63.2 percent. The number of the served patients fer a day showed that 20-30 accounted for 37.4 percent, while 30 persons or more for 25.7 percent. 53.4 percent of total subjects was unsatisfied with their duty quantity. And, the monthly salary indicated that 500,000 or less accounted for 72.3 percent. 3. The average marks by their job satisfaction factors indicated 4.42 for duty importance, 4.02 for recognization of specialized job, 3.98 for ability exercise, 1.99 for promotion possibility, 2.28 for reasonable salary, and 2.41 for welfare system, respectively, based on 5 full marks. 4. The summarized job satisfaction by factors indicated that the relation with the doctor accounted for 57.8 percent, the satisfaction status with the existing job for 53.4 percent, the ability development for 41.8 percent, respectively, and the salary for 10.2 percent. Then, the satisfaction by sex showed that the male was generally satisfied with the ability development (p<0.05), the relation with the doctor (p<0.01), and the satisfaction with the existing job, while the female was satisfied with the duty quantity(p<0.05), salary, and the situation guarantee (p<0.05). On the other hand, the satisfaction by age indicated that the subject of the lower age were satisfied with the ability development (p<0.01), the relation with the doctor(p<0.05), the salary, and the situation guarantee. Also, the satisfaction by the service section showed that the physical therapists serving at the general hospital were satisfied with the ability development (p<0.01), the duty quantity (p<0.01), the salary(p<0.01), the situation guarantee(p<0.01), and the satisfaction with the existing duty (p<0.05), while the physical therapists at the hospital and the rehabilitation center were unsatisfied with the salary (p<0.01). In addition, The satisfaction with the service period at the existing section indicated that the physical therapists less than 3 years were highly satisfied with the ability development, the relation with the doctor, the situation guarantee, and the existing duty(p<0.05), while the physical therapists more than 6 years tended to show the lower satisfaction, And the satisfaction with the monthly salary indicated that the higher the monthly salary, the higher the satisfaction with the relation to the doctor(p<0.05), the duty quantity(p<0.01), the salary(p<0.01), and the situation guarantee (p<0.01). 5. The correlation between general characteristics and job satisfaction factors indicated that the sex was directly correlated to the marital status (r=-0.442), while it was reversely correlated to the age (r=-0.564) , total career (r=-0.229), and the relation with the doctor (r=-0.233). Additionally, the age was directly correlated to the total carreer (r=-0.677), and the service period at the existing section (r=0.491), while the age was reversely correlated to the marital status (r=-0.678). Accordingly, the higher job satisfaction of the physical therapists was related to factors such as their duty importance, recognization of specialized occupation, ability exercise, autonomy, relation to colleagues, decision-making's consideration, and relation with the doctor, while the lower job satisfaction includes the opportunity of promotion, salary, welfare system, service time, duty quantity, and situation guarantee. For this reason, if the factors of the lower job satisfaction are solved, then it will be possible to encourage the motive of these physical therapists, and the acyivate their duties. More over, it is also possible to improve the medical service, Additionally, if the general physical therapy room in the hospital and in the public health center are established, more development should be accomplished in the physical therapy.

• Korean Journal of Weed Science
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• v.31 no.3
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• pp.260-270
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• 2011

This study was carried out to examine the effect of rice bran, barley bran, burned rice bran, and burned barley bran on the growth and yield of Chinese chive (Allium tuberosum Rottler), taro (Colocasia esculenta), and weed control. When the above 4 brans were examined 13, 27, 41 and 57 days respectively after application, the plant height of Chinese chive applied with burned barley bran was significantly higher than non-treated control, whereas the other brans did not have any distinct effect on the plant height or population number of Chinese chive. However, when examined 57 days after the application of the above 4 brans, all the plants applied with brans showed more than twice the improvement in shoot fresh weight compared with non-treated control. A chemical analysis of soil 57 days after the application of the above 4 brans showed that the soils were richer in available phosphate and organic matter. Shoot fresh weight of Chinese chive at 2 weeks after cutting was significantly higher in barely bran treated plot than in non-treated plot. In the case of taro, only taro plots transplanted when 10 cm tall and applied with barley bran showed an improvement in growth increment of both the underground and above parts. However, when sowed seeds after the application of the 4 brans, the yield of taro was reduced by the brans. Thus this research indicates that the effect of brans is differ based on the amount of bran application as well as crops. The effect of weed control on Echinochloa crus-galli, Digitaria clliaris, Chenopodium album, and Solanum nigrum as affected by brans was very low in pot conditions. Weed efficacy of the brans was also very low in field conditions. Growth of Chinese cabbage and garland chrysanthemum was inhibited 63% and 37% by rice bran at $4,000kg\;ha^{-1}$, respectively, but other crops such as maize, squash, cucumber, and Chinese chive were inhibited by 0-20%. These results were similar to that of barley bran except for Chinese cabbage.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.1
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• pp.63-75
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• 2012

This paper gives some basic requirements and preferences of various geological environmental conditions for the final deep geological repository of spent nuclear fuel (SNF). This study also indicates how the requirements and preferences are to be considered prior to the selection of sites for a site investigation as well as the final disposal in Korea. The results of the study are based on the knowledge and experience from the IAEA and NEA/OECD as well as the advanced countries in SNF disposal project. This study discusses and suggests preliminary guideline of the disposal requirements including geological, mechanical, thermal, hydrogeological, chemical and transport properties of host rock with long term geological stabilities which influence the functions of a multi-barrier disposal system. To apply and determine whether requirements and preferences for a given parameter are satisfied at different stages during a site selection and suitability assessment of a final disposal site, the quantitative criteria in each area should be formulated with credibility through relevant research and development efforts for the deep geological environment during the site screening and selection processes as well as specific studies such as productions of safety cases and validation studies using a generic underground research laboratory (URL) in Korea.

• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.322-331
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• 2017

District heating was first introduced in Korea in 1985. As the service life of the underground thermal piping network has increased for more than 30 years, the maintenance of the underground thermal pipe has become an important issue. A variety of complex technologies are required for periodic inspection and operation management for the maintenance of the aged thermal piping network. Especially, it is required to develop a model that can be used for decision making in order to derive optimal maintenance and replacement point from the economic viewpoint in the field. In this study, the analysis was carried out based on the repair history and accident data at the operation of the thermal pipe network of five districts in the Korea District Heating Corporation. A failure probability model was developed by introducing statistical techniques of qualitative analysis and binomial logistic regression analysis. As a result of qualitative analysis of maintenance history and accident data, the most important cause of pipeline damage was construction erosion, corrosion of pipe and bad material accounted for about 82%. In the statistical model analysis, by setting the separation point of the classification to 0.25, the accuracy of the thermal pipe breakage and non-breakage classification improved to 73.5%. In order to establish the failure probability model, the fitness of the model was verified through the Hosmer and Lemeshow test, the independent test of the independent variables, and the Chi-Square test of the model. According to the results of analysis of the risk of thermal pipe network damage, the highest probability of failure was analyzed as the thermal pipeline constructed by the F construction company in the reducer pipe of less than 250mm, which is more than 10 years on the Seoul area motorway in winter. The results of this study can be used to prioritize maintenance, preventive inspection, and replacement of thermal piping systems. In addition, it will be possible to reduce the frequency of thermal pipeline damage and to use it more aggressively to manage thermal piping network by establishing and coping with accident prevention plan in advance such as inspection and maintenance.