• Journal of the Semiconductor & Display Technology
• /
• v.7 no.4
• /
• pp.29-33
• /
• 2008

Rapid increase of integrity for recent semiconductor industry highly demands the development of removal technology of contaminated particles in the scale of a few microns or even smaller. It is known that the surface cleaning technology using $CO_2$ snow has its own merits of high efficiency. However, the detailed removal mechanism of particles using this technology is not yet fully understood due to the lack of sophisticated research endeavors. The detachment mechanism of particles from the substrates is known to be belonged in four types; rebounding, sliding, rolling and lifting. In this study, a modeling effort is performed to explain the detachment mechanism of a contaminant particle due to the rebounding caused by the vertical collision of the $CO_2$ snow. The Hertz and Johnson-Kendall-Roberts(JKR) theories are employed to describe the contact, adhesion and deformation mechanisms of the particles on a substrate. Numerical simulations are followed for several representative cases, which provide the perspective views on the dynamic characteristics of the particles as functions of the material properties and the initial inter-particle collision velocity.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.33 no.4
• /
• pp.55-73
• /
• 2020

Objectives : We investigated the effectiveness and safety of intranasal phototherapy for allergic rhinitis (AR). Methods : We searched 8 electronic databases (PubMed, Cochrane Library, CNKI, CiNii Articles, OASIS, NDSL, KISS, KMbase) to identify randomized controlled trials (RCTs) that reported the use of intranasal phototherapy for AR from their inception until May 30, 2020. Two investigators independently searched, collected, and screened the RCTs. We performed data extraction and evaluation for risk of bias using the Cochrane risk-of-bias tool. Results : This study included 12 RCTs; six studies compared intranasal and sham phototherapy, of which four studies reported a significant inter group difference and two studies reported a significant difference partially. No significant changes in symptoms were observed between the phototherapy and conventional therapy groups. The phototherapy and concurrent acupuncture treatment group showed a significantly higher effectiveness rate compared with the group that received only acupuncture. Both the phototherapy and laser acupuncture group showed significant improvement in the symptom severity scale scores. Six studies reported mild adverse effects, such as dryness and nasal pain in the intranasal phototherapy group; however, no severe adverse effects were reported. Conclusions : This study confirmed the safety and effectiveness of intranasal phototherapy for symptom relief and improved quality of life in patients with AR. However, further studies are needed on this topic in order to demonstrate it clearly.

• Advances in Traditional Medicine
• /
• v.6 no.2
• /
• pp.112-120
• /
• 2006

The purpose of this study was to analyze whether quantitative evaluation of the color of the tongue substance using $L^*a^*b^*$ color coordinates system could minimize the problems arising from the different illuminating conditions or not. In controlled 4 different illuminating conditions (by natural light, flashlight, f-number, shutter speed),12 healthy subjects were photographed of their tongue substance through a digital camera (C-2100uz, Olympus Co.), both on the top surface and on the bottom surface of the tongue substance by two examiners, twice at 3 day intervals. Clinician evaluation was also performed grading the redness of the tongue substance in the form of 5-points scale by 6 clinicians. As a result, there was no significant difference in color differences between the color of the tongue substance and the reference red card in the 4 different illuminating conditions. Intra-rater reliability was satisfied and even though limitedly, inter-rater reliability was satisfied. Color differences were significantly correlated with the results by the clinicians, although they were applicable limitedly to specific illuminating conditions. Our results indicate that the application of the color differences in tongue diagnosis could not only evaluate the color information quantitatively, but also minimize the problems arising from the different illuminating conditions and that there was the significant difference in the visual evaluation of the red color of the tongue substance, both between the clinicians and between the illuminating conditions.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.41 no.2
• /
• pp.1-8
• /
• 2018

K-means algorithm is one of the most popular and widely used clustering method because it is easy to implement and very efficient. However, this method has the limitation to be used with fixed number of clusters because of only considering the intra-cluster distance to evaluate the data clustering solutions. Silhouette is useful and stable valid index to decide the data clustering solution with number of clusters to consider the intra and inter cluster distance for unsupervised data. However, this valid index has high computational burden because of considering quality measure for each data object. The objective of this paper is to propose the fast and simple speed-up method to overcome this limitation to use silhouette for the effective large-scale data clustering. In the first step, the proposed method calculates and saves the distance for each data once. In the second step, this distance matrix is used to calculate the relative distance rate ($V_j$) of each data j and this rate is used to choose the suitable number of clusters without much computation time. In the third step, the proposed efficient heuristic algorithm (Group search optimization, GSO, in this paper) can search the global optimum with saving computational capacity with good initial solutions using $V_j$ probabilistically for the data clustering. The performance of our proposed method is validated to save significantly computation time against the original silhouette only using Ruspini, Iris, Wine and Breast cancer in UCI machine learning repository datasets by experiment and analysis. Especially, the performance of our proposed method is much better than previous method for the larger size of data.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.31 no.6 s.261
• /
• pp.635-643
• /
• 2007

As many engineers and technicians are involved in the design process of large scale and/or complex products, there are a lot of miss matches and interferences due to designers' faults and several kinds of CAD systems. Recently, CAD systems are applied to verify and check the assembly process. Digital Mock-Up(DMU) system, a tool to build a virtual mock-up in the design stage, has been used to prevent the interferences and miss matches during precision design processes. Using the virtual assembly tool, engineers are able to design precision and interference free parts without physical mock-ups. Instead of a single CAD source, several CAD systems are used to design a complex product. Several organizations are involved in the distributed design environment for heterogeneous multi-CAD assembly. XML and the lightweight CAD file are proposed for the multi-CAD assembly. XML data contains hierarchy of the heterogenenous multi-CAD assembly. STEP PDM schema and STEP ISO 10303-28 formations are applied to construct the XML data. The lightweight CAD file produced from various CAD files through ACIS kernel and InterOp not only contains mesn, B-Rep and topological data, but also is used to visualize CAD data and to verify dimensions. Developed system is executed on the desktop computers. It does not require commercial CAD systems to visualize 3D assembly data. Real-time interference and fitness checks, dimensional verification, and design and assembly verification are performed on the developed system. Assembly of heterogeneous models for a car is conducted to verify the effectiveness of the developed DMU system on the Internet.

• Imaging Science in Dentistry
• /
• v.47 no.3
• /
• pp.141-147
• /
• 2017

Purpose: The objective of this study was to compare the outcomes of surgical mini-implant placement when potential mini-implant sites were scanned using a lower-dose $180^{\circ}$ acquisition protocol versus a conventional $360^{\circ}$ acquisition protocol. Materials and Methods: Ten dentate human skulls were used to provide sites for potential mini-implant placement. The sites were randomly divided into 2 groups: $360^{\circ}$ and $180^{\circ}$ cone-beam computed tomography (CBCT) acquisition protocols. A small-volume $180^{\circ}$ CBCT scan and a $360^{\circ}$ CBCT scan of each site were acquired using a Morita Accuitomo-170 CBCT machine and then a mini-implant was placed. A follow-up $360^{\circ}$ CBCT scan was done as a gold standard to evaluate the location of the mini-implant and root perforation. Two raters evaluated the scans. Results: Ninety-eight percent of the mini-implants placed did not perforate any root structure. Two percent of the sites had an appearance suggestive of perforation. On a Likert scale, both raters agreed that their subjective evaluation of the diagnostic quality of the protocols, ability to make and read measurements of the sites, and preferences for the specified diagnostic task were comparable. The Cohen kappa showed high inter-rater and intrarater agreement. Conclusion: In this ex vivo study, we found that the $180^{\circ}$ rotational acquisition was as effective as the conventional $360^{\circ}$ rotational acquisition for the preoperative evaluation of potential mini-implant sites.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.9
• /
• pp.67-74
• /
• 2008

This paper proposes, designs and implements an architecture of a server involved with the network camera based video surveillance systems to solve common problems including lack of inter-network operability at the video information sharing, drawback of bandwidth and processing-overhead caused by increase of the number of users, and difficulty of continuous monitoring over changes of network configurations. The proposed saver was designed to manage and service numerous network cameras and users as well as solving the existing problems by providing video distribution facility. Through the empirical study after applying the implemented server to a real video surveillance system we proved that the server can provide reasonable service quality while it processes several hundreds of simultaneous user connections under persisting more than one hundred connections to network cameras. We expect the developed video distribution server to enhance service quality of the large scale video surveillance systems for citizen-wide services such as traffic reporting informatics or natural calamities supporting.

• Journal of Power Electronics
• /
• v.11 no.5
• /
• pp.759-766
• /
• 2011

This paper focuses on monitoring and predicting the short circuit faults of the rotor windings of large turbo-generator systems. For the purpose of increasing efficiency and decreasing maintenance cost, a method that combines the HHT (Hilbert Huang Transform) with a wavelet has been studied. This method is based on analyzing a classical Albright detecting coil. Due to the Empirical Mode Decomposition (EMD) and the Intrinsic Mode Functions (IMF) of the HHT the exact location of a short circuit of rotor windings may be given. However, a part of the useful information is eliminated by the unreasonable decomposing scale of the wavelet. Based on the thermodynamics modeling method, this study was illustrated with a 50MW turbo-generator system that is installed in Northern China. The analysis results, which have very good agreement with those of a previous study, show that the method of combining the HHT with a wavelet is an effective way to analyze and predict the short circuit faults of the rotor windings of large generators, such as supercritical turbo-generator systems and wind turbo-generator systems. This work can offer a useful reference for analyzing smart grids by improving the power quality of a distribution network that is supplied by a turbo-generator system.

• Land and Housing Review
• /
• v.3 no.2
• /
• pp.195-202
• /
• 2012

This paper summarizes the seismic performance of two shear walls with different reinforcement details in boundary elements. One is a special shear wall designed by KBC2009 and the other is a shear wall with improved reinforcement details in boundary elements, which is a newly proposed type of special shear wall. Experimental tests under cyclic reversed loading were carried out with two 2/3 scale shear walls which were modelled from the lower part of seismic-resisting shear wall in 22-stories wall-slab apartment building. The experimental results show that seismic performance of shear wall with improved reinforcement details was almost similar to that of special shear wall with respect to the moment-drift ratio. However, energy dissipation capacity and ductility were slightly different. Also, shear wall with improved reinforcement details in boundary elements satisfied the inter-story drift limit of 1.5% from KBC2009.

• Journal of Korean Academy of Nursing
• /
• v.49 no.5
• /
• pp.526-537
• /
• 2019

Purpose: The aim of this study was to evaluate the validity and reliability of the Korean version of the Clinical Teaching Behavior Inventory (CTBI). Methods: The English CTBI-23 was translated into Korean with forward and backward translation. Survey data were collected from 280 nurses' preceptors at five acute-care hospitals in Korea. Content validity, construct validity, and criterion-related validity were evaluated. Cronbach's ${\alpha}$ was used to assess reliability. SPSS 24.0 and AMOS 22.0 software was used for data analysis. Results: The CTBI Korean version consists of 22 items in six domains, including being committed to teaching, building a learning atmosphere, using appropriate teaching strategies, guiding inter-professional communication, providing feedback and evaluation, and showing concern and support. One of the items in the CTBI was excluded with a standardized factor loading of less than .05. The confirmatory factor analysis supported good fit and reliable scores for the Korean version of the CTBI model. A six-factor structure was validated ($x^2=366.30$, p<.001, CMIN/df=2.0, RMSEA=.06, RMR=.03, SRMR=.05, GFI=.90, IFI=.94, TLI=.92, CFI=.94). The criterion validity of the core competency evaluation tool for preceptors was .77 (p<.001). The Cronbach's ${\alpha}$ for the overall scale was .93, and the six subscales ranged from .72 to .85. Conclusion: The Korean version CTBI-22 is a valid and reliable instrument for identifying the clinical teaching behaviors of preceptors in Korea. The CTBI-22 also could be used as a guide for the effective teaching behavior of preceptors, which can help new nurses adapt to the practicalities of nursing.