• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.3
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• pp.203-215
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• 2010

This study is an overview of toxicities and measurement techniques of ultrafine particles (UFPs), and their exposure controls. UFPs are ubiquitous in many working situations. Exposure to UFPs is possibly causing adverse health symptoms including cardio-respiratory disease to humans. In order to measure exposure levels of airborne UFPs, there are current available measurement guidelines, instruments and other techniques (i.e. contour mapping, control banding). However, these risk assessment techniques including measurement techniques, controls and guidelines are dependent on background levels, metrics (e.g. size, mass, number, surface area, composition), environmental conditions and controls. There are no standardized measurement methods available and no generic and specific occupational exposure standards for UFPs. It is thought that there needs to be more effort to develop Regulations and Exposure Standards for generic UFPs should be based on more exposure data, health surveys, toxicological data and epidemiological data. A carefully considered hierarchy of controls can also reduce the maximum amount of airborne UFPs being emitted from diverse sources in industries.

• Communications for Statistical Applications and Methods
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• v.10 no.2
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• pp.507-517
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• 2003

Self-organizing map (SOM) has been developed mainly by T. Kohonen and his colleagues as a unsupervised learning neural network. Because of its topological ordering property, SOM is known to be very useful in pattern recognition and text information retrieval areas. Recently, data miners use Kohonen´s mapping method frequently in exploratory analyses of large data sets. One problem facing SOM builder is that there exists no sensible criterion for evaluating goodness-of-fit of the map at hand. In this short communication, we propose valid evaluation procedures for the Kohonen SOM of any size. The methods can be used in selecting the best map among several candidates.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.8
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• pp.62-71
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• 2009

In mobile robotics, ultrasonic sensors became one of the most popular devices for collision avoidance and navigation primarily due to data robustness, the easy availability of low-cost systems, their compact size, simple circuits, and their ease in interfacing with computers. However, ultrasonic sonic sensors are subject to noise which results in inaccuracy of mapping and localization of the robot. This paper introduces a new approach to enhance environmental maps based on ultrasonic range data using linear interpolation and Newton interpolation. The simulation and experimental results show that the proposed method improves of the accuracy of the map through better distance estimation between the mobile robot and obstacles.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.4
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• pp.575-581
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• 1998

In order to accommodate current accelerated growth in customers and traffic. Internet has faced the demand to scale its network dimension both in size and bandwidth, and new service provisioning. One way to solve this problem is to forward If packets based on ATM switching technology. This paper briefly explained technical tasks to apply this If switching technique in ATM networks for building Internet backbone, and presented the directions to approach these tasks. Those tasks are scalability, ATM VC setup and mapping between VC and IP packet flow, traffic management and traffic engineering, multicast, and finally ATM switch architecture to provide multiservice.

• Journal of Korea Multimedia Society
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• v.7 no.12
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• pp.1700-1707
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• 2004

Nowaday, market size of digital image in world around is looks to rapidly growth. For this, Texture mapping has traditionally been used to add realism to computer graphics images. Therefore to make our image realistic, we need to give the various kind of objects material parameter and environment lighting. To present the completed marble we use passing back algorithm and combination with channel of a material. In experimental result of this paper that application by passing back algorithm and varying the parameter such as scale, period, distortion, octaves of noise make showing the superiority of optimized rendering of spheres and perfect another marble effects.

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.698-705
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• 2014

We propose a new development for calculating a computer-generated hologram (CGH) through the use of multiple general-purpose graphics processing units (GPGPUs). For optimization of the implementation, CGH parallelization, object point tiling, memory selection for object point, hologram tiling, CGMA (compute to global memory access) ratio by block size, and memory mapping were considered. The proposed CGH was equipped with a digital holographic video system consisting of a camera system for capturing images (object points) and CPU/GPGPU software (S/W) for various image processing activities. The proposed system can generate about 37 full HD holograms per second using about 6K object points.

• Journal of the Korean Society for Library and Information Science
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• v.49 no.1
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• pp.129-148
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• 2015

This study grasped the true nature of the inquiry domain by analysing the requests for collaborative reference service in the social science field using the co-word technique, and schematized the intellectual structure. First, this study extracted 748 uncontrolled keywords from inquiries for reference in the field of social science. Second, calculated similarity indices between the words on the basis of co-occurrence frequency, and performed not only clustering but also MDS mapping. Third, to grasp the difference in inquiries for reference by period, dividing the period into two parts, and performed comparative analysis. As a result, there formed 5 clusters and "Korea Education" showed an overwhelming size with 40.3% among those clusters. The result of the analysis through the period division showed there were many questions about "Education" during the first half, while a lot of inquiries with focus on "welfare and business information" during the second half.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.8
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• pp.1178-1186
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• 1989

In this paper, a systolic array for polyadic-nonserial DP problems is designed, the performance is analyzed and the efficient operating method is proposed. The algorithm is transformed to remove the broadcasting and global communication paths in the data dependence step by step. The transformed algorithm is mapping to the systolic array using the method proposed by D. I. Moldovan. The designed array is homogenous, had the processing elements of (n+1)/2 and 2n computation time ( n is the size of problem). In case of being many problems to process, the efficiency of array can be upward by inputing the problems successively. The interval between the initiations of two successive proboem instances is [n/2]+1 and the speed-up is about 4. The processor utilizations of each case are calculated.

• Current Optics and Photonics
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• v.3 no.6
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• pp.566-570
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• 2019

To investigate dependence of the sensitivity of THz metamaterials on the position of target dielectric materials, we functionalized the metamaterial gap with an adhesive polymer. A shift in resonance frequency occurs when polystyrene microbeads are deposited in the gap of the metamaterial's metal resonator pattern, while little change is observed when they are deposited on other areas of the metasurface. A two-dimensional mapping of the sensitivity, with a grid size of 1 ㎛, is obtained from a finite-difference time-domain simulation: The frequency shift is displayed as a function of the position of a target dielectric cube. The resulting sensitivity distribution clearly reveals the crucial role of the gap in sensing with metamaterials, which is consistent with the electric field distribution near the gap.

• Archives of Plastic Surgery
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• v.41 no.3
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• pp.225-230
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• 2014

The increased application of the da Vinci robotic platform (Intuitive Surgical Inc.) for microsurgery has led to the development of new adjunctive surgical instrumentation. In microsurgery, the robotic platform can provide high definition $12{\times}-15{\times}$ digital magnification, broader range of motion, fine instrument handling with decreased tremor, reduced surgeon fatigue, and improved surgical productivity. This paper presents novel adjunctive tools that provide enhanced optical magnification, micro-Doppler sensing of vessels down to a 1-mm size, vein mapping capabilities, hydro-dissection, micro-ablation technology (with minimal thermal spread-$CO_2$ laser technology), and confocal microscopy to provide imaging at a cellular level. Microsurgical outcomes from the use of these tools in the management of patients with infertility and chronic groin and testicular pain are reviewed. All these instruments have been adapted for the robotic console and enhance the robot-assisted microsurgery experience. As the popularity of robot-assisted microsurgery grows, so will its breadth of instrumentation.