• The Journal of Korean Academy of Prosthodontics
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• v.32 no.1
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• pp.120-147
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• 1994

This study was performed for the purpose of evaluating the stress distribution around threaded type implants, cylindrical type implants and teeth connected with rigid or non-rigid connector. The stress distribution around the surrounding bone was analyzed by three-dimensional photoelastic method. Twelve mandibular photoelastic epoxy resin models and a circular polariscope were used to record the isochromatic fringes. After the stress distribution around the implant and tooth was observed, the results were as follows ; 1. In threaded type implants, stress concentrated patterns were observed at the neck either vertical or 25 degree lateral force. 2. The stress concentrated patterns were observed at the tooth apical portion and neck portions of the implant and tooth when a threaded implant was connected with the tooth by either a rigid or non-rigid connector. More force was generated at the tooth neck portion by a rigid connector and more force at the implant neck portion by a non-rigid connector. 3. The stress concentrated patterns were observed at the apical portion of the implant and tooth when a cylindrical type ,implant was connected with the tooth either by a rigid or non-rigid connector. More force was generated at the tooth apical portion by a rigid connector and more force at the neck portion of the tooth and implant by a non-rigid connector. 4. The stress around the tooth was more equally distributed in a threaded type implant than in a cylindrical implant when the tooth was connected with either a rigid or non-rigid connector. 5. The stress around a threaded type implant was progressively more equally distributed in the following order : 1) when used a single implant, 2) a non-rigid connection with the implant and tooth, 3) a rigid connection with the implant and tooth, 4) a rigid connection with two implant fixtures.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.447-457
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• 2008

Laboratory tests for single plane sliding were conducted using the model rock slope to investigate the cut slope deformability and failure mechanism due to combined effect of engineering characteristics such as angle of sliding plane, water force, joint roughness and infillings. Also the possibility of prediction of slope failure through displacement monitoring was explored. The joint roughness was prepared in forms of saw-tooth type having different roughness specifications. The infillings was maintained between upper and lower roughness plane from zero to 1.2 times of the amplitude of the surface projections. Water force was expressed as the percent filling of tension crack from dry (0%) to full (100%), and constantly increased from 0% at the rate of 0.5%/min and 1%/min upto failure. Total of 50 tests were performed at sliding angles of $30^{\circ}$ and $35^{\circ}$ based on different combinations of joint roughness, infilling thickness and water force increment conditions. For smooth sliding plane, it was found that the linear type of deformability exhibited irrespective of the infilling thickness and water force conditions. For sliding planes having roughness, stepping or exponential types of deformability were predominant under condition that the infilling thickness is lower or higher than asperity height, respectively. These arise from the fact that, once the infilling thickness exceeds asperities, strength and deformability of the sliding plane is controlled by the engineering characteristics of the infilling materials. The results obtained in this study clearly show that the water force at failure was found to increase with increasing joint roughness, and to decrease with increasing filling thickness. It seems possible to estimate failure time using the inverse velocity method for sliding plane having exponential type of deformability. However, it is necessary to estimate failure time by trial and error basis to predict failure of the slope accurately.

• Journal of the Economic Geographical Society of Korea
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• v.18 no.1
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• pp.87-102
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• 2015

This study attempts to introduce the methodology for accounting real-time population distribution in the urban areas. For the purpose, we utilize the media user's time-space information from the media users' media diaries in the media panel survey databases. We analyze the space-time population rate for each activity space related with everyday urban lifes. Seoul has been selected as a case study area, since space-time information are relatively rich there, and thus the comparisons are available. The space-time population rates have been verified by the comparative analysis with the T-card results. We propose a real time population measurement method by combination of the space-time population rate with geographical data. The real time population of each activity space at each dong in Seoul has been calculated by multiplying the space-time population rates to the numbers of employer of three categories of activity spaces(residential, working, and commercial). By utilizing GIS, we visualize the results of two time points (3AM and 3PM) and then analyze the spacio-temporal characteristics of real time population distribution in Seoul. The Day time population distribution pattern shows strong relationships with the distribution of business and commercial activities, while the night time population distribution pattern can be explained by resident population distribution almost perfectly.

• Journal of the Korean Institute of Gas
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• v.5 no.4 s.16
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• pp.1-7
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• 2001

This paper presents a 'consequence analysis' for vapor cloud explosions caused by heavy gas leakages from commercially used storage tanks at petrochemical plants. Particularly, this paper emphasizes on evaluating the results of various vapor cloud explosion accidents from Butane storage tanks. Also this paper analyses the impact of variables on the accidents in order to acquire the optimum conditions for variables. $SuperChems^{TM}$ Professional Edition was applied to analyse the impact (If atmospheric and other variables in the situation where vapor cloud continuously disperses from the ground level. Under the assumption that practical operating conditions are selected as a standard condition, and Butane leaks from the storage tank for 15 minutes, the results show that the maximum distance of LFL (Lower Flammable Limit) was 52 meters and overpressure by the vapor cloud explosion was 1 psi at 128.2 meters. It is observed that the impact of the variables on accidental Butane storage tank leakage mainly varied upon atmospheric stability, wind velocity, pipe line size, visible length, etc., and changes in the simulation result occurred as the variables varied. The maximum distance of the LFL (Lower Flammable Limit) increased as the visible length became shorter, the size of the leak became larger, the wind velocity was decreased, and the climatic conditions became more stable. Thus, by analysing the variables that influence the simulation results of explosions of Butane storage tanks containing heavy gases, I am presenting the most appropriate method for 'consequence analysis' and the selection of standards for suitable values of variables, to obtain the most optimal conditions for the best results.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.34 no.1
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• pp.97-106
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• 2016

This study is to suggest the necessity of landscaping alternatives for succession of Takjok(濯足) culture by considering the background and meaning of Takjok's cultural phenomenon shown in old literatures, paintings and ruins of landscape architecture as a front morphemes. Its result is as follows. 1. An old idiom, 'Takyung Takjok(濯纓濯足)' implying a disinterested living attitude from the mundane world and an attitude complying with the nature, has been sublimated to 'Takjokjiyu(濯足之遊)' which means living in comfortable retirement through life in seclusion(隱逸). 2. The meaning of Takjok did not expand into, not only Takyung Takjok, but also into Takcheong(濯淸), Tako(濯吾), and Taksa(濯斯) with continued expansion in its meaning. The spaces the meaning of Takyung Takjok is implied on have also newly expanded into the artificial spaces, including Jeong(亭-pavilion) Jae(齋-house) Heon(軒-eaves), and Ji(池-pond), as well as the natural spaces, including Am(巖-rock) Dae(臺-flat foundation) Dam(潭-deep pond) Ban(盤-dish rock) Seok(石-stone) So(沼-shallow pond) San(山-mountain) Bong(峰-peak), and Cheon(泉-water hole). 3. As seen here, the cultural phenomenon of Takyung Takjok, which have derived from the Dangho(堂號) of buildings, the names of natural objects in Palgyung and Gugok(eight sceneries and nine curves), facilities of Byeolseo garden and Seowon, and the Amgakseo in nature, is worth noting. 4. It should be considered that Takjok includes ordinary people's wisdom to resist the hot weather as well as classical scholar's ideal and the veneration of antiquity. From this perspective, water space, Takjok rocks, and use of water based on the environmental supportability should be newly focused as a recreational space and it reminds us that the spirit of Takjok is a classical mental healing method.

• Journal of Broadcast Engineering
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• v.16 no.1
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• pp.23-32
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• 2011

Design and Implementation of Clipcast Service via Terrestrial DMB This paper outlines the system design and the implementation process of clipcast service that can send clips of video, mp3, text, images, etc. to terrestrial DMB terminals. To provide clipcast service in terrestrial DMB, a separate data channel needs to be allocated and this requires changes in the existing bandwidth allocation. Clipcast contents can be sent after midnight at around 3 to 4 AM, when terrestrial DMB viewship is low. If the video service bit rate is lowered to 352 Kbps and the TPEG service band is fully used, then 320 Kbps bit rate can be allocated to clipcast. To enable clipcast service, the terminals' DMB program must be executed, and this can be done through SMS and EPG. Clipcast service applies MOT protocol to transmit multimedia objects, and transmits twice in carousel format for stable transmission of files. Therefore, 72Mbyte data can be transmitted in one hour, which corresponds to about 20 minutes of full motion video service at 500Kbps data rate. When running the clip transmitted through terrestrial DMB data channel, information regarding the length of each clip is received through communication with the CMS(Content Management Server), then error-free files are displayed. The clips can be provided to the users as preview contents of the complete VOD contents. In order to use the complete content, the user needs to access the URL allocated for that specific content and download the content by completing a billing process. This paper suggests the design and implementation of terrestrial DMB system to provide clipcast service, which enables file download services as provided in MediaFLO, DVB-H, and the other mobile broadcasting systems. Unlike the other mobile broadcasting systems, the proposed system applies more reliable SMS method to activate the DMB terminals for highly stable clipcast service. This allows hybrid, i.e, both SMS and EPG activations of terminals for clipcast services.

• Journal of Korean Society of Forest Science
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• v.94 no.6
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• pp.496-503
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• 2005

This study was conducted to investigate the influences of sapflow flux on soil water tensions and soil moisture content at the Abies holophylla plots in Gwangneung, Gyeonggido, from September to October 2004. The Abies holophylla had been planted in 1976 and thinning and pruning were carried out in 1996 and 2004. Sapflow flux was measured by the heat pulse method, and soil water tension was measured by tensiometer at hillslope and streamside. Time domain reflectometry probes (TDR) were positioned horizontally at the depth of 10, 30 and 50 cm to measure soil moisture content. All of data were recorded every 30 minutes with the dataloggers. The sapflow flux responded sensitively to rainfall, so little sapflow was detected in rainy days. The average daily sapflow flux of sample trees was 10.16l, a maximum was 15.09l, and a minimum was 0.0l. The sapflow flux's diurnal changes showed that sapflow flux increased from 9 am and up to 0.74 l/30 min. The highest sapflow flux maintained by 3 pm and decreased almost 0.0 l/30 mm after 7 pm. The average soil water tensions were low ($-141.3cmH_2O$, $-52.9cmH_2O$ and $-134.2cmH_2O$) at hillslope and high ($-6.1cmH_2O$, $-18.0cmH_2O$ and $-3.7cmH_2O$) at streamside. When the soil moisture content decreased after rainfall, the soil water tension at hillslope responded sensitively to the sapflow flux. The soil water tension decreased as the sapflow flux increased during the day time, whereas increased during the night time when the sapflow flux was not detected. On the other hand, there was no significant relationship between soil water tension and sapflow flux at streamside. Soil moisture content at hillslope decreased continuously after rain, and showed a negative correlation to sapflow flux like a soil water tension at hillslope. As considered results above, it was confirmed that the response of soil moisture tension to sapflow flux at hillslope and streamside were different.

• Journal of Hospice and Palliative Care
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• v.22 no.1
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• pp.8-18
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• 2019

Purpose: This study was conducted to better understand the illness experiences and palliative care needs in community-dwelling persons with cardiometabolic diseases. Methods: This qualitative descriptive study was conducted with 11 patients (and three family members) among 28 patients contacted. Interviews were led by the principal investigator in her office or at participants' home depending on their preference. All interviews were digitally recorded and transcribed by a research assistant. The interviews were analyzed by two independent researchers using a conventional method. Results: Participants' ages ranged from 42 to 82 years (nine men and two women). Three themes were identified: (1) same disease, but different illness experiences; (2) I am in charge of my disease(s); (3) preparation for disease progression. Participants were informed of the name of their disease when they were diagnosed, but not provided with explanation of the diagnosis or meant or how to do self-care to delay the disease progression, which increased the feelings of uncertainty, hopelessness and anxiety. Taking medication was considered to be the primary treatment option and self-care a supplemental one. Advanced care plans were considered when they felt the progression of their disease(s) while refraining from sharing it with their family or health care professionals to save their concerns. All participants were willing to withhold life-sustaining treatment without making any preparation in writing. Conclusion: Education on self-care and advanced care planning should be provided to community-dwelling persons with cardiometabolic diseases. A patient-centered education program needs to be developed for this population.

• Journal of Chest Surgery
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• v.40 no.5 s.274
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• pp.362-368
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• 2007

Background: Spontaneous pneumothorax patients with blebs or bullae are considered to be good candidates for operation, and various objective diagnostic modalities have been performed for detection of blebs and bullae. This study was performed to compare the efficacy of thoracoscopic examination with using a minimally invasive 2 mm thoracoscope with high-resolution computed tomography (HRCT) for treating primary spontaneous pneumothorax. Material and Method: From June 2001 to March 2002, 34 patients with spontaneous pneumothorax undewent study with 2 mm video-thoracoscopic examination and HRCT. We regarded a blob larger than 5 mm in diameter as significant. Standard thoracoscopic wedge resection was performed in 18 patients with significant blob via a 2 mm video-thoracoscopic examination. 1 patient incurred bleeding, and the remaining 15 patients were treated with pleural drainage. Result: Multiple or single blob lesions were detected by 2 mm video-thoracoscope in 52.9% (18/34) of the patients with primary pneumothorax. For a total of 19 patients who were operated on, the diagnostic accuracy of the 2 mm video-thoracoscopic examination for bullae and blob was 94.7% (18/19), which was superior to that of HRCT (73.7%, 14/19). At a mean follow-up of $30{\pm}3$ months, no recurrence occurred in both the operative group and the non-operative group. Conclusion: 2 mm video-thoracoscopic examination under local anesthesia has higher diagnostic accuracy than HRCT, and it is a useful alternative for determining the operative indications for spontaneous pneumothorax.

• Economic and Environmental Geology
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• v.46 no.1
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• pp.51-61
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• 2013

Researches on the oil recovery enhancement using the nanotechnology has recently been studied in the United States. The previous researches has focused mainly on the flow characteristics of nanoparticles in porous media, and the stability of the nano-emulsion itself. However, the analysis did not deal with the size effects between a nano-emulsion and the pore size which has an important role when nano-emulsion flows in the porous media. In this research, nano-based emulsion was fabricated which is able to be applied for the enhanced oil recovery techniques and its characteristics was analyzed. In addition, in order to identify the characteristics of nano-emulsions flowing through the porous media, the size effect was analysed by filtering test. According to the results, when the emulsion was fabricated, SCA(Silane Coupling Agent) or PVA(Poly Vinyl Alcohol) are added to improve the stability of emulsion. As the ratio of the decane to water increased, the viscosity of emulsion and the droplet size also increased. For the filtering test at the atmospheric conditions, the droplet did not go through the filter; only the separated water from the emulsion was able to be filtered. This phenomenon occurred because the droplet was not able to overcome the capillary pressure. At the filtering test by suction pressure, most of the emulsion was filtered over the filter size of $60{\mu}m$. However, the ratio of filtration was rapidly degraded at less than $45{\mu}m$ filters. This is caused due to deformation and destruction of the droplet by strong shear stress when passing through the pore. The results from the study on the basic characteristic of nano-emulsion and filtering test will be expected to play as the important role for the fabrication of the stable nano-emulsion or the research on the recovery of residual oil in porous media.