• Korean Journal of Computational Design and Engineering
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• v.7 no.3
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• pp.148-156
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• 2002

Most Rapid Prototyping (RP) processes adopt a solid Computer Aided Design (CAD) model, which will be sliced into thin layers of constant thickness in the building direction. Each cross-sectional layer is successively deposited and, simultaneously, bonded onto the previous layer; and eventually the stacked layers from a physical part of the model. A new RP process, the transfer-type Variable Lamination Manufacturing process using expandable polystyrene foam sheet (VLM-ST), has been developed to reduce building time and to improve the surface finish of parts with the thick layers and a sloping surface. This paper describes the generation of Unit Shape Layer (USL), the cutting path data of the linen. hotwire cutter for the VLM-ST process. USL is a three-dimensional layer with a thickness of more than 1 mm and a side slope, and it is the basic unit of cutting and building in the VLM-ST process. USL includes data such as layer thickness, positional coordinates, side angles of each layer, hotwire cutting speed, the heat input to the hotwire, and reference shape. The procedure of generating USL is as follows: (1)Generation of the mid-slice from the CAD model, (2)Conversion of the mid-slice into a simply connected domain, (3)Generation to the reference shape for the mid-slice, (4)Calculation of the rotation angle of the hotwire of the cutting system.

• Journal of the Korean Geotechnical Society
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• v.40 no.3
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• pp.77-84
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• 2024

Aging and damaged underground utilities cause cavity and ground subsidence under roads, which can cause economic losses and risk user safety. This study used infrared cameras to assess the thermal characteristics of such cavities and evaluate their reliability using a CNN algorithm. PVC pipes were embedded at various depths in a test site measuring 400 cm × 50 cm × 40 cm. Concrete blocks were used to simulate road surfaces, and measurements were taken from 4 PM to noon the following day. The initial temperatures measured by the infrared camera were 43.7℃, 43.8℃, and 41.9℃, reflecting atmospheric temperature changes during the measurement period. The RP algorithm generates images in four resolutions, i.e., 10,000 × 10,000, 2,000 × 2,000, 1,000 × 1,000, and 100 × 100 pixels. The accuracy of the CNN model using RP images as input was 99%, 97%, 98%, and 96%, respectively. These results represent a considerable improvement over the 73% accuracy obtained using time-series images, with an improvement greater than 20% when using the RP algorithm-based inputs.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.9 s.174
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• pp.194-201
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• 2005

Recently, as Rapid Prototyping is attracting people's attention, many peoples are actively participating in the research on STL format. The STL files are transformed to be input for RP after modeling in CAD system. When the shape, however, needs to be changed or edited, it is impossible without the original data. So, if the original data is lost, new modeling is required. Therefore, this study suggests a way to edit the shape in STL format and to make the Boolean operation possible between the original and edited shapes. In addition, the reliability was confirmed after going over the errors of the edited data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.14-21
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• 2020

In order to provide confidential services between two communicating parties, block data encryption using a symmetric secret key is applied. A power analysis attack on a cryptosystem is a side channel-analysis method that can extract a secret key by measuring the power consumption traces of the crypto device. In this paper, we propose an attack model that can recover the secret key using a power analysis attack based on a deep learning convolutional neural network (CNN) algorithm. Considering that the CNN algorithm is suitable for image analysis, we particularly adopt the recurrence plot (RP) signal processing method, which transforms the one-dimensional power trace into two-dimensional data. As a result of executing the proposed CNN attack model on an XMEGA128 experimental board that implemented the AES-128 encryption algorithm, we recovered the secret key with 22.23% accuracy using raw power consumption traces, and obtained 97.93% accuracy using power traces on which we applied the RP processing method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8B
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• pp.822-829
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• 2009

A reader protocol is an interface between a host and RFID readers. There are several standards for reader protocol such as EPCglobal Low Level Reader Protocol (LLRP) 1.0.1, EPCglobal Reader Protocol (RP) 1.1, and ISO/IEC 15961/15962. Unfortunately, these standards focus on the passive RFID system, and so they are not appropriate for the active RFID system. In this paper, we implemented an efficient reader protocol for the active RFID system, which is based on EPCglobal LLRP 1.0.1, but smoothing/filtering functions of EPCglobal RP 1.1 are added. This protocol is designed to configure air interface parameters for active RFID readers and tags. It can reduce the amount of data transfer between the reader and host by filtering function, and can improve the performance of tag collection by smoothing function. In addition, it can remove inefficiency caused by tag memory data change according to the standards of ISO/IEC 15961/15962. In the real-world environment, we evaluated the performance of our implemented reader protocol using one RFID reader and 45 tags.

• Restorative Dentistry and Endodontics
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• v.44 no.1
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• pp.9.1-9.9
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• 2019

Objectives: The aim of this study was to compare postoperative pain intensity after root canal treatment with One G (OG) vs. R-Pilot (RP) files used for glide path preparation. Materials and Methods: Ninety-three single-canaled mandibular premolar teeth with asymptomatic non-vital pulp were randomly assigned into 3 groups (n = 31): OG, RP, or without glide path (WGP). After creating the glide path, the root canals were prepared using sequential Mtwo rotary files to size 30/0.05. One endodontic specialist carried out single-visit endodontic treatment. The patients were asked to rate the severity of postoperative pain on a visual analogue scale at 24, 48, and 72 hours after the visit. They were also asked to record their intake of prescribed analgesics taken. The data were analyzed using the ${\chi}^2$, Friedman, Kruskal-Wallis, and Mann-Whitney U tests. Results: In all 3 groups, postoperative pain decreased significantly at each time interval (p < 0.05). At 24 hours, the OG group had less postoperative pain than the WGP group (p < 0.05). However, no significant difference was found between the RP group and the others. No statistically significant difference was found among the WGP, OG, and RP groups in postoperative pain intensity at 48 or 72 hours or in analgesic tablet intake at the 3 assessed time intervals. Conclusions: The OG group had less postoperative pain than the WGP group in the first 24 hours. The OG and RP systems were similar regarding postoperative pain intensity and analgesic intake.

• The KIPS Transactions:PartC
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• v.10C no.6
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• pp.809-814
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• 2003

The multicast transmitting the real-time data to groups may easily have many attacks from abnormal attacks because it has many links as compared to the unicast. The existing group key management architectures for preventing these problems are designed for protocols suitable for a large scale. Thus these architectures applied to a small scale routing protocols may have many overheads with key distribution and a constant core tree. Therefore this paper proposes a groups key management protocol for a secure multicast in PIM-SM multicast group communication. The proposed method divide multicast groups with RO(Rendezvous-Point), and subgroup key managers are established in each RP and can be transmitted groups keys between senders and receivers, so the security cannel is set up for secure data transfer, And this does not have needs of the data translation for group keys and the new key distribution for path change. As a result of this, the data transmission time can be reduced.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.321-326
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• 1997

This paper present how VRML file format can be used for RP Technology. VRML standards provids compact and powerful interface between remote RP manufacturer in network independent environment. We have constructed integrated and network-connected server system which can share the CAD data and varios process which is STL-to-VRML translater,slicing process,slice anchor process etc. This Server system consisted in file converter between STL and VRML,CGI system which sends a generated data to VRML client or browser, slice-generator which can re-slice at varied thickness and simulator which can show and check simultaneously status between near slices with support. This system aims to the integrated simulator which supports graphic animator and FEA analysis system.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.179-182
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• 2002

Rapid Prototyping (RP) technologies provide the ability to fabricate initial prototypes from various model materials. Stratasys' Fused Deposition Modeling (FDM) is a typical RP process that can fabricate prototypes out of plastic materials, and the parts made from FDM were often used as load-carrying elements. Because FDM deposits materials in about $300\mutextrm{m}$ thin filament with designated orientation, parts made from FDM show anisotropic material properties. This paper proposes an analytic model to predict the tensile strength of FDM parts. Applying the Classical Lamination Theory, which was developed for laminated composite materials, a computer code was implemented. Tsai-Wu failure criterion was added to the code to predict the failure of the FDM parts. The tensile strengths predicted by the analytic model were compared with experimental data. The data and prediction agreed reasonably well to prove the validity of the model. In addition, a web-based advisory service was developed to provide to strength prediction and design rules for FDM parts.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.9
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• pp.13-19
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• 2003