• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.166-169
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• 2018

캐시 부채널 공격 중 하나인 FLUSH+RELOAD 공격은 높은 해상도와 적은 오류로 그 위험성이 높고, 여러가지 프로그램에서도 적용되어 개인정보의 유출에 대한 위험성까지 증명 되었다. 따라서 이 공격을 막기 위해 실시간으로 감지 할 수 있어야 할 필요성이 있다. 본 연구에서는 4가지 실험을 통하여 이 FLUSH+RELOAD 공격을 받을 때 PCM(Performance Counter Monitor)를 사용해 각각의 counter들의 값의 변화를 관찰하여 3가지 중요한 요인에 의해 공격 탐지를 할 수 있다는 것을 발견하였다. 이를 이용하여 머신 러닝의 logistic regression과 ANN(Artificial Neural Network)를 사용해 결과에 대한 각각 학습을 시킨 뒤, 실시간으로 공격에 대한 탐지를 할 수 있는 프로그램을 제작하였다. 일정한 시간동안 공격을 진행하여 모든 공격을 감지하는데 성공하였고, 상대적으로 적은 오탐률을 보여주었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.5188-5193
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• 2011

This research is for temperature control of insulating oil inside the transformer. After I designed and manufactured various systems using Peltier element, which was thermal element, and Heat pipe, which was a cooling system, without electric power. The optimum system could be made by applying them to the temperature control for the insulating oil. I could verify that the combination type of Heat pipe 100 W+ Peltier 100W has a more outstanding capacity than pure Heat pipe 300 W within 60 degrees Celsius through experiments. Through this, I verify that the method of a proper design is prominent, and make an attempt at contribution to power saving effect and more effective control of Distributing board by using this combination type.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.4
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• pp.117-124
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• 2018

USA and Europe are leading the transport airplane industry. In Asia-Pacific region, air transportation and MRO industries are forecasted to be grown up rapidly. Furthermore, Japan and China entered into design and manufacture state of regional airplane, while developing countries entered into severe struggle competition for MRO industry. Global aircraft MRO and engine MRO industries are forecasted 3.4% and 7% annual growth respectively in the next decade. In this paper, authors propose promotion strategy for technology intensive MRO of aircraft engine to create a higher value-added business.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.1
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• pp.67-70
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• 2022

In the present work, we have designed to optimize the optical filter structures of the 1-dimensional photonic quasicrystals (1D PQCs) characteristic for the COVID-19 UV sterilization. The simulator using MATLAB program and ourselves manufacturing calculation codes. After making the aperiodic (and complexed) multi-layer structure model, we establish the transfer matrix method (TMM) for model by the operator conversion. By the using the MATLAB, we derive a matrix for the designed complexed multi-layer structure by applying the equations to the model by obtaining the reflectance and transmittance from the matrix. We also prove the possibility of application in optical filter for UV sterilization.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.6 s.348
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• pp.53-61
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• 2006

In high speed flash type or pipelining type A/D Converter, the faster sampling frequency is, the more the effect of DC reference fluctuation is increased by clock feed-through and kick-back. When we measure A/D Converter, further, external noise increases reference voltage fluctuation. Thus reference fluctuation reduction circuit must be needed in high speed A/D converter. Conventional circuit simply uses capacitor but layout area is large and it's not efficient. In this paper, a reference fluctuation reduction circuit using transmission gate is proposed. In order to verify the proposed technique, we designed and manufactured 6bit 2GSPS CMOS A/D converter. The A/D converter is based on 0.18um 1-poly 5-metal N-well CMOS technology, and it consumes 145mW at 1.8V power supply. It occupies chip area of $977um\times1040um$. Experimental result shows that SNDR is 36.25 dB and INL/DNL ${\pm}0.5LSB$ when sampling frequency is 2GHz.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.6
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• pp.25-34
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• 2012

New calibration method for the near-field scanning (NFS) system is presented. The proposed calibration method consisted of a new near-field antenna (NFP) and newly devised patterns as circular patch patterns (CPPs) and meander patterns (MPs). The proposed patterns were used for improving spatial resolutions and simplifying a calibration procedure of the NFP compared to the conventional method defined in the IEC61967-3 and 6. Also, the effect of the length of NFPs on attenuation characteristics was investigated with length of 8mm and 30mm. For them, we designed and fabricated CPPs of diameter (D) = 20, 40, 60, and 100mm and MPs of various widths and spaces. We found the reverse relations between spatial resolutions and heights of measuring points by using simplified calibration procedure. The testing result shows that the spatial resolution of $120{\mu}m$ at height of $200{\mu}m$ was verified without complex correlation algorithms under 8GHz. For manufacturing cost all patterns and the NFP were realized with low-cost fabrication using PCB (FR-4) not by a conventional LTCC process. For verification of chip-level EMC from the results, near-field scanning system (NFSS) having step resolution of Sub-micron scale was produced and by using the proposed NFSS and proposed NFP measurement of chip shows accurately the shape of the resolution of $200{\mu}m$ patterns for securing a high level of chip-level EMC verification.

• Journal of IKEEE
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• v.17 no.1
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• pp.1-9
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• 2013

The quantitative evaluation of DEM(Digital Elevation Map) is very important to the assessment of the effectiveness for the applied 3D image analysis technique. This paper presents a new quantitative evaluation method of 3D reconstruction process by using synthetic images. The proposed method is based on the assumption that a preacquired DEM and ortho-image should be the pseudo ground truth. The proposed evaluation process begins by generating a pair of photo-realistic synthetic images of the terrain from any viewpoint in terms of application of the constructed ray tracing algorithm to the pseudo ground truth. By comparing the DEM obtained by a pair of photo-realistic synthetic images with the assumed pseudo ground truth, we can analyze the quantitative error in DEM and evaluate the effectiveness of the applied 3D analysis method. To verify the effectiveness of the proposed evaluation method, we carry out the quantitative and the qualitative experiments. For the quantitative experiment, we prove the accuracy of the photo-realistic synthetic image. Also, the proposed evaluation method is experimented on the 3D reconstruction with regards to the change of the matching window. Based on the fact that the experimental result agrees with the anticipation, we can qualitatively manifest the effectiveness of the proposed evaluation method.

• Journal of radiological science and technology
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• v.29 no.4
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• pp.225-228
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• 2006

Purpose: Accurate clinical evaluation of the alignment of the calcaneus relative to the tibia in the coronal plane is essential in the evaluation and treatment of hindfoot pathologic condition. Previously described standard anteroposterior, lateral, and oblique radiographic methods of the foot or ankle do not demonstrate alignment of the tibia relation to the calcaneus in the coronal plane. The purpose of this study was to introduce hindfoot coronal alignment view. Material : 1) Both feet were imaged simultaneously on an elevated, radiolucent foot stand equipment. 2) Both feet stood on a radiolucent platform with equal weight on both feet. 3) Both feet are located foot axis longitudinal perpendicular to the platform. 4) Silhouette tracing around both feet are made, and line is then drawn to bisect the silhouette of the second toe and the outline of the heel. 5) The x-ray beam is angled down approximately $15^{\circ} to $20^{\circ} Result : 1) This image described tibial axis and medial, lateral tuberosity of calcaneus. 2) Calcaneus do not rotated. 3) The view is showed by talotibial joint space. Conclusion: Although computed tomographic and magnetic resonance imaging techniques are capable of demonstrating coronal hindfoot alignment, they lack usefulness in most clinical situations because the foot is imaged in a non-weight bearing position. But hindfoot coronal alignment view is obtained for evaluating position changing of inversion, eversion of the hindfoot and varus, valgus deformity of calcaneus.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.1
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• pp.91-104
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• 2008

Recently, osseointegrated implants have been used to improve denture support, stability, and retention. Several studies have been revealed that mandibular two-implant overdentures significantly increase patient satisfaction with the function of their prostheses. Use of a wide variety of attachment systems, including stud, magnet, and bar attachments, has proven both clinically predictable and effective. This article presents that two-implant overdenture can become the standard of care for treatment of the edentulous mandible.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.2
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• pp.137-143
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• 2010

Complete dryness inside the stator is a necessary and sufficient condition for the leak test. Microcracks caused by high cycle fatigue due to operation are generated in stator windings, and they are interrupted by water molecules during the leak test. For this reason, during leak test, the wrong value is indicated when there are no leaks in stator windings. Generator manufacturers presents unique dryness judgment criteria for the leak test, but there is no actual criterion that accurately indicates the dryness point for the leak test. The reason is because stator winding has a complex structure and the absence of effective dryness equipment in power plants. This paper proposes a dryness judgment criterion to evaluate if inside the stator winding is dried completely and presents experimental results.