• Journal of Periodontal and Implant Science
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• v.43 no.6
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• pp.308-314
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• 2013

Purpose: The purposes of this study were to assess the dentists' subjective satisfaction with the crestal approach sinus (CAS) kit, a device for maxillary sinus membrane elevation by the crestal approach using a special drilling system and hydraulic pressure, and to summarize the subjective satisfaction of dental implants placed after a sinus lift procedure with the CAS kit. Methods: Thirty dental clinicians who had experience with dental implant placement after a sinus lift procedure with the CAS kit from June 2010 to May 2012 were included in this study. The questionnaire for the evaluation of the dentists' subjective satisfaction with the CAS kit was sent to the respondents and returned. The questionnaire was composed of two main parts. The first part was related to the sinus membrane perforation rate. The second part was related to the dentists' subjective satisfaction with the CAS kit. Results: A total of 28 dentists answered the questionnaire. Among 924 implant cases, sinus membrane perforation occurred in 38 cases (4.1%). Among the 28 dentists, 26 dentists (92.9%) were satisfied or very satisfied with the CAS kit. In particular, 24 dentists (85.7%) reported that safety, cutting performance, and user-friendliness of the CAS drill were advantages of the CAS kit. However, 7 dentists (25%) did not routinely use the hydraulic lifter for sinus membrane elevation. Conclusions: From the survey, it was shown that the respondents were generally satisfied with the CAS kit and that the cutting performance and safety of the drill component were considered strengths of the CAS kit.

• Food Science of Animal Resources
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• v.32 no.6
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• pp.763-768
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• 2012

This study has been performed to measure the prevalence and microbial flora on chicken slaughtering as well as the processing process from the months of October to November. Whole-chicken rinsing technique was used in order to analyze the incidence of microorganisms on chicken carcass at the stage before chilling (after evisceration), after chilling and after cutting. The swab technique was used on processing the processed samples, such as working plates and cutting knives. Brine and cooling water from four cooling tubs were taken from each processing processes and were used as samples. Furthermore, the matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) for whole cell fingerprinting in combination with a dedicated bioinformatic software tool was used to identify the isolated microorganisms. Of the tested samples and processes, brine ($4.50{\pm}0.64$ Log CFU/mL) and chicken carcass before chilling ($4.15{\pm}0.46$ Log CFU/mL) showed the highest population of microorganisms; the predominant microbial flora of them were Moellerella wisconsensis (54.84%), a member of the Enterobacteriaceae family, and Escherichia coli (60.36%), respectively. However, the predominant microbial flora of cut carcass was changed to Staphylococcus aureus (27.32%), which is a kind of pathogenic microorganism that can cause a food-borne illness. Therefore, the slaughtering and processing procedure of chicken are needed to be controlled more hygienically.

• International Journal of CAD/CAM
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• v.4 no.1
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• pp.33-45
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• 2004

In this work, a rational procedure has been formulated for the selection of points approximating slice contours cut in LOM (Laminated Object manufacturing) with first order approximation. It is suggested that the number of points representing a slice contour can be 'minimised' or 'optmised' by equating the horizontal chordal deviation (HCD) to the user-defined surface form tolerance. It has been shown that such optimization leads to substantial reduction in slice height calculations and NC codes file size for cutting out the slices. Due to optimization, the number of contour points varies from layer to layer, so that points on successive layer contours have to be matched by four sided ruled surface patches and triangular patches. The technological problems associated with the cutting out of triangular patches have been addressed. A robust algorithm has been developed for the determination of slice height for optimum and arbitrary numbers of contour points with different strategies for error calculations. It has been shown that optimisation may even lead to detection and appropriate representation of elusive surface features. An index of optimisation has been defined and calculations of the same have been tabulated.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.10
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• pp.45-52
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• 1999

The online realtime positioning error compensation system 'SKY-PACS' is developed to correct geometric errors, thermal errors and tool deflection errors induced by cutting forces on the vertical machining center. 'SKY-PACS' communicates position commands and position compensation signals with the CNC controller at 100Hz, which is CNC control frequency. So the compensation procedure can be applied during axis movement. Using 'SKY-PACS', Maximum 1 axis positioning accuracy was corrected from 5{\mu}m$ to 2{\mu}m$and the squareness error of X-Y table was corrected from 51{\mu}m$/m to below 4{\mu}m$/m. The error compensation under the cutting condition is carried out by ISO10791-7. And the measurement of test-pieces shows that the roundness is corrected rom 8{\mu}m$ to below 5{\mu}m$.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.7
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• pp.32-45
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• 1995

In this paper, we present a new method to tool path planning problem for rough cut of pocket milling operations. The key idea is to formulate the tool path problem into a TSP (Travelling Salesman Problem) so that the powerful neural network approach can be effectively applied. Specifically, our method is composed of three procedures: a) discretization of the pocket area into a finite number of tool points, b) neural network approach (called SOM-Self Organizing Map) for path finding, and c) postprocessing for path smoothing and feedrate adjustment. By the neural network procedure, an efficient tool path (in the sense of path length and tool retraction) can be robustly obtained for any arbitrary shaped pockets with many islands. In the postprocessing, a) the detailed shape of the path is fine tuned by eliminating sharp corners of the path segments, and b) any cross-overs between the path segments and islands. With the determined tool path, the feedrate adjustment is finally performed for legitimate motion without requiring excessive cutting forces. The validity and powerfulness of the algorithm is demonstrated through various computer simulations and real machining.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.7
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• pp.71-79
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• 2002

A new rapid prototyping process, Variable Lamination Manufacturing using a 4-axis-controlled hotwire cutter and expandable polystyrene foam sheet as a laminating material of the part (VLM-S), has been developed to reduce building time and to improve the surface finish of parts. The objective of this study is to reconstruct the surface of the original 3D CAD model in order to generate mid-slice data using the advancing front technique. The generation of 3D layers by a 4 axis-controlled hot-wire cutter requires a completely different procedure to generate toolpath data unlike the conventional RP CAD systems. The cutting path data for VLM-S are created by VLM-Slicer, which is a special CAD/CAM software with automatic generation of 3D toolpath. For the conventional sheet type system like LOM, the STL file would be sliced into 2D data only. However, because of using the thick layers and a sloping edge with the firstorder approximation between the top and bottom layers, VLM-Slicer requires surface reconstruction, mid-slice, and the toolpath data generation as well as 2D slicing. Surface reconstruction demands the connection between the two neighboring cross-sectional contours using the triangular facets. VLM-S employs thick layers with finite thickness, so that surface reconstruction is necessary to obtain a sloping angle of a side surface and the point data at a half of the sheet thickness. In the process of the toolpath data generation the surface reconstruction algorithm is expected to minimize the error between the ruled surface and the original parts..

• Journal of the Korean Society for Precision Engineering
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• v.15 no.8
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• pp.46-59
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• 1998

This paper presents shape design, surface construction, and cutting path generation for the surface of marine ship propeller blades. A propeller blade should be designed to satisfy performance constraints that include operational speed which impacts rotations per minutes, stresses related to deliverable horst power, and the major length of the marine ship which impacts the blade size and shape characteristics. Primary decision variables that affect efficiency in the design of a marine ship propeller blade are the blade diameter and the expanded area ratio. The blade design resulting from these performance constraints typically consists of sculptured surfaces requiring four or five axis contoured machining. In this approach a standard blade geometry description consisting of blade sections with offset nominal points recorded in an offset table is used. From this table the composite Bezier surface geometry of the blade is created. The control vertices of the Hazier surface patches are determined using a chord length fitting procedure from tile offset table data. Cutter contact points and path intervals are calculated to minimize travel distance and production time while maintaining a cusp height within tolerance limits. Long path intervals typically generate short tool paths at the expense of increased however cusp height. Likewise, a minimal tool path results in a shorter production time. Cutting errors including gouging and under-cut, which are common errors in machining sculptured surfaces, are also identified for both convex and concave surfaces. Propeller blade geometry is conducive to gouging. The result is a minimal error free cutting path for machining propeller blades for marine ships.

• Tuberculosis and Respiratory Diseases
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• v.70 no.1
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• pp.43-50
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• 2011

Background: Open lung biopsy is used for diagnosis of diffuse infiltrative lung diseases (DILD), but it is invasive and relatively expensive procedure. Fluoroscopy-guided cutting needle lung biopsy (FCNLB) has merits of avoidance of admission and rapid diagnosis. But diagnostic accuracy and safety were not well known in the diagnosis of DILD. Methods: We included 52 patients (37 men, 15 women) having DILD on HRCT with dyspnea, except the patients who could be confidently diagnosed with clinical and HRCT findings. FCNLB was performed using 16G Ace cut needle (length 1.5 cm, diameter 2 mm) at the area of most active lesion on HRCT. Final diagnoses were made by the consensus. Results: The mean interval between the HRCT and FCNLB was 4.5 days. Most cases were performed one biopsy during 5~10 minutes. Specific diagnosis was obtained in 43 of 52 biopsies (83%). The most common diagnosis was nonspecific interstitial pneumonia (11 cases) and followed by cryptogenic organizing pneumonia (7 cases), diffuse alveolar hemorrhage and usual interstitial pneumonia (5 cases in each), hypersensitivity pneumonitis (3 cases), tuberculosis and drug induced interstitial pneumonitis (2 cases in each), the others are in one respectively. Mild complication was developed in 9 patients (8 pneumothorax, 1 hemoptysis). Most of complications were regressed without treatment except one case with chest tube insertion for pneumothorax. Conclusion: Fluoroscopy-guided 16 G cutting needle lung biopsy was an useful method for the diagnosis of DILD.

• Journal of Korean Society of Forest Science
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• v.100 no.2
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• pp.240-245
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• 2011

Vegetation changes were studied for 16 yr in clearcut logged Pinus densiflora forests in the southern Gangwon-do province in Korea by applying chronosequence approach. Ambient temperature and relative humidity, Detrended Correspondence Analysis (DCA), Multiple Responses Permutation Procedure (MRPP), Indicator Species Analysis (ISPAN) were used to examine successional trajectory and compositional changes. After clearcutting, canopy openness was increased abruptly at three folds (1yr 68.3% and R1 23.0%) and then decreased, but relative moisture was slightly decreased (6%) compare to control site. In the result of DCA, right after clear cutting, vegetation composition was developed heterogeneously compared to control sites, and then approached to control sites within 16 years. Based on MRPP, species composition of each developmental stages (1yr, 3yr, 10yr and 16yr) revealed signigicant differences to that of control vegetation (R1, R3, R10 and R16). Indicator species in 1yr and 3yr samples included various woody species rather than herbaceous species, but in 10yr and 16yr, herbaceous were more abundant. Earlier succession of pine forests likely can explain to Initial Floristic Composition (IFC) Model.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.4
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• pp.637-642
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• 2010

Pre-treatment steps of fresh produce as Saengshik raw materials are followed by initial clean-up, dipping, primary washing, and cutting. Hypochlorous acid solution was applied in the dipping step to reduce natural microflora. Also, procedures were changed by cutting, dipping and then primary washing, and the efficacy of hypochlorus acid was evaluated. Potatoes, carrots, kales, and angelicas were submerged in water or 100 ppm of hypochlorous acid for 5 min. After initial clean-up, the aerobic plate counts of potatoes, carrots, kales and angelicas were 4.7, 5.3, 5.6, and 5.7 log CFU/g, respectively. When samples were submerged into water, it only reduced the population of natural microflora by 0.2 to 1.1 log CFU/g, whereas when treated with hypochlorous acid, it reduced the population by 0.5 to 2.8 log CFU/g. Reductions of natural microflora in green leafy vegetables were more highly achieved than bulbs such as potatoes and carrots. However, the numbers of natural microflora were increased after cutting step. To control the cross contamination at the cutting process, the process was changed as follows: initial clean-up, cutting, dipping in hypochlorous acid, and then primary washing. It showed effective reduction of the population by 2.3 to 3.2 log CFU/g. Hypochlorous acid solution could be useful as a sanitizer for surface washing of fresh vegetables.