• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.2
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• pp.70-76
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• 2017

The purpose of this study was to perform a literature review of short implants in the posterior maxilla and to assess the influence of different factors on implant success rate. A comprehensive search was conducted to retrieve articles published from 2004 to 2015 using short dental implants with lengths less than 10 mm in the posterior maxilla with at least one year of follow-up. Twenty-four of 253 papers were selected, reviewed, and produced the following results. (1) The initial survival rate of short implants in the posterior maxilla was not related to implant width, surface, or design; however, the cumulative success rate of rough-surface short implants was higher than that of machined-surface implants especially in performance of edentulous dental implants of length <7 mm. (2) While bone augmentation can be used for rehabilitation of the atrophic posterior maxilla, short dental implants may be an alternative approach with fewer biological complications. (3) The increased crown-to-implant (C/I) ratio and occlusal table (OT) values in short dental implants with favorable occlusal loading do not seem to cause peri-implant bone loss. Higher C/I ratio does not produce any negative influence on implant success. (4) Some approaches that decrease the stress in posterior short implants use an implant designed to increase bone-implant contact surface area, providing the patient with a mutually protected or canine guidance occlusion and splinting implants together with no cantilever load. The survival rate of short implants in the posterior edentulous maxilla is high, and applying short implants under strict clinical protocols seems to be a safe and predictable technique.

• Journal of The Korea Institute of Healthcare Architecture
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• v.19 no.3
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• pp.21-28
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• 2013

Purpose: General hospital in korea is getting large-scaled, specialized and upgraded. So, nursing unit of race track type has been advanced along with a spatial organization, building equipment and environmental approach. This study is to search the guidelines for renovation of nursing unit with race track type in the case of K university hospital in Daejeon. Methods: 9 cases of recently opened general hospital has been analyzed for spatial and environmental design solution. Questionnaires and interviews about user needs of nursing staff, patient and visitors, have been conducted for a nursing care system and facility of nursing units in K university hospital. Results: The user needs are represented as followings. Center core public zone in each floor plan and center core nursing station and supporting areas in nursing unit are good for an adjacency and separation of spatial organization. Toilet of group patient room is necessary to equip for easy, safe and infective aspects, and so toilet install will decrease the patient number and increase the nursing care service. Hall type of station front is good for visibility and observation. It is appropriate to renovate into south facing group patient room for privacy, enough space for nursing care facility and supporting area, enough width of door to move portable medical equipment, room for medical doctor and practical student, noise absorbing of day room. Implications: Upgrading the nursing care service and facility equipment is necessary to reflect the user needs and cooperate with hospital management.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.1
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• pp.47-53
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• 2007

Satellite image mosaicking is essential for image interpretation and analysis especially for a large area such as the Korean Peninsula. This paper proposed the technique of automatic seam-line extraction and the method of creating image mosaic in automated fashion. The seam-line to minimize artificial discontinuity was extracted using Minimum Absolute Gray Difference Sum algorithm with constraint condition on search-area width and Canny Edge Detection algorithm. To maintain the radiometric balance among images acquired at different time epochs, we utilized Match Cumulative Frequency method. Experimental results showed that edge detection algorithm extracted the seam-lines significantly well along linear features such as roads and rivers.

• Journal of the Institute of Convergence Signal Processing
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• v.6 no.1
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• pp.1-7
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• 2005

This paper describes the system for detecting vehicles in the rear and rear-side that access between sidewalk and bus stopped to city road at day by computer vision-based method. This system informs appearance of vehicles to bus driver and passenger for the safety of a bus passenger getting off. The camera mounted on the top portion of the bus exit door gets the rear and rear-side image of the bus whenever a bus stops at the stop. The system sets search area between bus and sidewalk from this image and detects a vehicle by using change of image and sobel filtering in this area. From a central point of the vehicle detected, we can find out the distance, speed and direction by its location, width and length. It alarms the driver and passengers when it's judged that dangerous situation for the passenger getting off happens. This experiment results in a detection rate more than 87% in driving by bus on the road.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.64.2-64.2
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• 2019

HD 81817 is known as a hybrid star. Hybrid stars have both cool stellar wind properties and UV or even X-ray emission features of highly ionized atoms in their spectra. A white dwarf companion has been suggested as the source of UV or X-ray features. HD 81817 has been observed since 2004 as a part of our radial velocity (RV) survey program to search for exoplanets around K giant stars using the Bohyunsan Observatory Echelle Spectrograph (BOES) at the 1.8 m telescope of Bohyunsan Optical Astronomy Observatory (BOAO) in Korea. We obtained 84 RV measurements between 2004 and 2018 for HD 81817 and found two periodic RV variations. The obtained amplitudes of RV periods are around 200 m/s, which are significantly lower than that expected from a white dwarf companion. Furthermore, our re-analysis of the IUE spectra used by Reimers (1984) shows that the excess in UV emission can easily be explained by a pseudo-continuum of unresolved emission lines originating in the extended chromosphere of the star. We thus conclude that there are no companions of stellar mass to HD 81817. Meanwhile, we analyzed two periodicities in RV measurements and conclude that the period of 627.9 days is caused by intrinsic stellar activities based on H alpha equivalent width (EW) variations of a similar period. On the other hand, the period of 1047.8 days is likely to be caused by substellar companion which has a minimum mass of 27.6 M_JUP, a semi-major axis of 3.3 AU, and an eccentricity of 0.17 assuming the stellar mass of 4.3 M_⊙ for HD 81817. The inferred mass puts HD 81817 b in the brown dwarf desert.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.3
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• pp.26-67
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• 2020

Synthetic Aperture Radar(SAR) is able to photograph the earth's surface regardless of weather conditions, day and night. Because of its possibility to search for hydrological factors such as soil moisture and groundwater, and its importance is gradually increasing in the field of water resources. SAR began to be mounted on satellites in the 1970s, and about 15 or more satellites were launched as of 2020, which around 10 satellites will be launched within the next 5 years. Recently, various types of SAR technologies such as enhancement of observation width and resolution, multiple polarization and multiple frequencies, and diversification of observation angles were being developed and utilized. In this paper, a brief history of the SAR system, as well as studies for estimating soil moisture and hydrological components were investigated. Up to now hydrological components that can be estimated using SAR satellites include soil moisture, subsurface groundwater discharge, precipitation, snow cover area, leaf area index(LAI), and normalized difference vegetation index(NDVI) and among them, soil moisture is being studied in 17 countries in South Korea, North America, Europe, and India by using the physical model, the IEM(Integral Equation Model) and the artificial intelligence-based ANN(Artificial Neural Network). RADARSAT-1, ENVISAT, ASAR, and ERS-1/2 were the most widely used satellite, but the operation has ended, and utilization of RADARSAT-2, Sentinel-1, and SMAP, which are currently in operation, is gradually increasing. Since Korea is developing a medium-sized satellite for water resources and water disasters equipped with C-band SAR with the goal of launching in 2025, various hydrological components estimation researches using SAR are expected to be active.

• Korean Journal of Environment and Ecology
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• v.28 no.5
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• pp.495-499
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• 2014

To search for myrmecochorous plant species, related ant species and diaspore selecting behaviour, collecting fruits and diaspores of four Corydalis species, cafeteria experiments, and the related ant species were studied from May 2013 to July 2014. Four Corydalis species recording in Korea were proved myrmecochorous (seed attached elaiosome) plants newly. Elaiosome shape of these species is spatulate-shaped, but their size is varied considerably in length and width. Significant differences is proved between four plant species in weight of diaspores, seeds and elaiosomes, and elaiosome ratios. Mean values of diaspores weight showed 4.08 mg, 2.56 mg, 2.49 mg and 2.06 mg in Corydalis grandicalyx, C. remota, C. turtschaninovii for. pectinata and C. turtschaninovii var. linearis, respectively. Mean values of seed weights showed 3.68 mg, 2.03 mg, 1.90 mg and 1.67 mg in Corydalis grandicalyx, C. remota, C. turtschaninovii for. pectinata and C. turtschaninovii var. linearis, respectively. Elaiosome ratio of C. turtschaninovii var. linearis was the highest, followed by C. remota, C. turtschaninovii for. pectinata and C. grandicalyx. Ant's preference for the diaspores is ordered as same as elaiosome ratio's order. Major ant species transporting the diaspores of Corydalis species are Formica japonica, Lasius alienus, Lasius japonicus and Tetramorium tsushimae. Formica japonica transports the diaspores most frequently. Ant's preference for the diaspores among plant species or individuals might be influenced on the survival rates of concerned species. Further studies on the myrmecochorous plant and related ant species, cafeteria experiments should be needed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.1
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• pp.122-131
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• 1992

An expert system is developed which can design the power transmission involute cylindrical gears on the basis of strength and durability. Bending strength, surface durability, scoring, and wear probability are considered as the basis. The basic components of the expert system are knowledge base, inference engine, and working memory. The knowledges in knowledge base are classified hierarchically into the knowledges used in selection of gear type, selection of materials, and determination of K factor and are represented by rules. In the inference engine two inference methods are implemented with the depth first search method. For-ward chaining method is introduced in the selection of gear type and materials and in the determination of K factor. Backward chaining method is introduced in the detailed design of module and face width in accordance with the validation of strength. And inference efficiency is achieved by constructing the part needing a lot of numerical calculations in strength estimation separately from inference mechanism. The working memory is established to save the results during inference temporarily. In addition, design database of past design results is built for consultation during design and knowledge acquisition facility, explanation facility, and user interface are included for the usefulness of user. This expert system is written with the PROLOG programming language and the FORTRAN language in numerical calculation part which interfaced with PROLOG and can also be executed on IBM-PC compatible computer operated by MS-DOS alone.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.10
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• pp.192-199
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• 2000

The design of multi-stage gear drives is a time-consuming process because it includes more complicated problems, which are not considered in the design of single-stage gear drives. The designer has no determine the number of reduction stages and the gear ratios of each reduction stage. In addition, the design problems include not only dimensional design but also configuration design of gear drive elements. There is no definite rule or principle for these types of design problems. Thus the design practices largely depend on the sense and the experiences of the designer, and consequently result in undesirable design solution. A new and generalized design algorithm has been proposed to support the designer at the preliminary phase of the design of multi-stage gear drives. The proposed design algorithm automates the design process by integrating the dimensional design and the configuration design process. The algorithm consists of four steps. In the first step, the user determines the number of reduction stages. In the second step, gear ratios of every stage are chosen using the random search method. The values of the basic design parameters of a gear are chose in the third step by using the generate and test method. Then the values of the dimensions, such as pitch diameter, outer diameter and face width, are calculated for the configuration design in the next step. The strength and durability of each gear is guaranteed by the bending strength and the pitting resistance rating practices by using AGMA rating formulas. In the final step, the configuration design is carried out using simulated annealing algorithm. The positions of gears and shafts are determined to minimize the geometrical volume (size) of a gearbox while avoiding interferences between them. These steps are carried out iteratively until a desirable solution is acquired. The proposed design algorithm is applied to the preliminary design of four-stage gear drives in order to validate the availability. The design solution has considerably good results in both aspects of the dimensional and the configuration design.

• Journal of IKEEE
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• v.9 no.1 s.16
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• pp.19-30
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• 2005

Packet classification is defined as the action to match the packet with a set of predefined rules. One of classification is to use Ternary Content Addressable Memory hardware search engine that has faster than other algorithmic methods. However, TCAM has some limitations. One of them is that TCAM can not perform range matching efficiently. A range has to be expanded into prefixes to fit the boundary. In general, the number of expansion could be up to 2w-2, where w is the width of the field. For example, if two range fields with 16 bits are used, there could be up to $30\;{\times}\;30\;=\;900$ expansions for a single rule. In this paper, we describe the novel algorithm for converting range matching rules into TCAM entry efficiently. The number of maximum entry is 2w-4 when using the algorithm. Furthermore, it has also benefit about the negation range. In the result of experimentation, the new scheme practically reduces 14 percent in case that searched fields are source port and destination port number.