• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.1
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• pp.33-43
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• 2023

The National Institute of Standards and Technology (NIST), which is working on the Post-Quantum Cryptography (PQC) standardization project, announced four algorithms that have been finalized for standardization. In this paper, we demonstrate through experiments that private keys can be exposed by Correlation Power Analysis (CPA) and Differential Deep Learning Analysis (DDLA) attacks on polynomial coefficient-wise multiplication algorithms that operate in the process of generating signatures using CRYSTALS-Dilithium algorithm. As a result of the experiment on ARM-Cortex-M4, we succeeded in recovering the private key coefficient using CPA or DDLA attacks. In particular, when StandardScaler preprocessing and continuous wavelet transform applied power traces were used in the DDLA attack, the minimum number of power traces required for attacks is reduced and the Normalized Maximum Margines (NMM) value increased by about 3 times. Conseqently, the proposed methods significantly improves the attack performance.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.773-776
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• 2013

We have prepared 1-D BiSI and 2-D BiOI nanostructures, and characterized them by scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction crystallography, thermogravimetric analysis/differential scanning calorimetry, and UV-visible absorption. Here, we first report clear HR-TEM image of BiSI. In addition, we first found that the growth direction of BiSI is [12-1] plane, with the neighboring distance of 0.30 nm. The crystal structures of BiSI and BiOI are found to be orthorhombic (Pnam) and tetragonal (P4/nmm), respectively. The absorption band gaps of BiSI and BiOI are measured to be 1.55 and 1.92 eV, respectively. Our study could further highlight the applications of V-VI-VII compounds.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.3
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• pp.1-10
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• 1995

In this paper, a fault-tolerant Mini-MAP system with high reliability is proposed. For fault-tolerance, the LLC sublayer, MAC sublayer, and physical layer of the Mini-MAP system are dualized. The detection of faults, the replacement of the failed network, and the management of the network are three major functions required for the dualization, and they are performed by ESM(Error Supervisory Machine), EMM(Error Management Machine), and NMM(Network Management Machine) of the proposed fault-tolerant Mini-MAP system, respectively. The ring maintenance function of the MAC sublayer is used for the detection of the faults. In the proposed fault-tolerant Mini-MAP system, the data are received from both of the dualized networks and transmitted to the selected one of the two. We analyze the reliability and the MTTF(Mean Time To Failure) of the proposed fault-tolerant Mini-MAP system and show that it has better performance compared to a general Mini-MAP system.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.1
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• pp.25-32
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• 2013

This study has been conducted in order to propose Eco-friendly and High functional waterproofing technology available for structure by verifying application and performance of water proofing material(s) in purpose of making effective use of reclaimed rubber. As s result of 12 months evaluation, stable performance for water pressure and lateral pressure of $0.3N/mm^2$ were confirmed. Also, as the time elapsed, the amount of water absorption and adhesion performance showed only a slight difference(+0.05g, $-0.1Nmm^2$) as well, which in turn confirmed that waterproofing performance remains stable. Studies show that it is expected to expand recycling technology of natural rubber by applying reclaimed rubber on construction waterproofing field, and to hold a technical superiority by using eco-friendly material in construction waterproofing market throughout active application of these types of research.

• Applied Microscopy
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• v.34 no.4
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• pp.255-264
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• 2004

The three-dimensional (3D) structure of an inorganic crystal, $SmZn_{0.67}Sb_2$ (space group P4/nmm, $a=4.26{\AA}\;and\;c=10.37{\AA}$) was solved by electron crystallography. High resolution electron microscopy (HREM) images from 3 different major zone axes and selected-area electron diffraction patterns from 16 different zone axes were combined to obtain a 3D information. A crystallographic image processing (CIP) of HREM images was used for more accurate determination of the crystal structure. As a result of this electron crystallography, average phase errors (${\Phi}_{res}$) of [001], [100] and [110] HREM images are $17.0^{\circ},\;8.3^{\circ}\;and\;21.9^{\circ}$, respectively. Xray crystallography of $SmZn_{0.67}Sb_2$ has attempted to compare accuracy of the structure determination by electron crystallography, which resulted in the cell parameters of $a=4.2976(6){\AA}\;and\;c=10.287(2){\AA}$, and the R-factor ($R_{sym}$) of 4.16%.

• Atmosphere
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• v.17 no.4
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• pp.327-337
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• 2007

In this study, we examined the new ensemble training approach to reduce the systematic error and improve prediction skill of wind by using the Short-range Ensemble prediction system (SENSE), which is the mesoscale multi-model ensemble prediction system. The SENSE has 16 ensemble members based on the MM5, WRF ARW, and WRF NMM. We evaluated the skill of surface wind prediction compared with AWS (Automatic Weather Station) observation during the summer season (June - August, 2006). At first stage, the correction of initial state for each member was performed with respect to the observed values, and the corrected members get the training stage to find out an adaptive weight function, which is formulated by Root Mean Square Vector Error (RMSVE). It was found that the optimal training period was 1-day through the experiments of sensitivity to the training interval. We obtained the weighted ensemble average which reveals smaller errors of the spatial and temporal pattern of wind speed than those of the simple ensemble average.

• Communications for Statistical Applications and Methods
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• v.16 no.6
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• pp.925-936
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• 2009

There very many approaches to impute missing values in the iid. case. However, it is hardly found the imputation techniques in the Markov random field(MRF) case. In this paper, we show that the imputation under MRF is just to impute by fitting the normal mixture model(NMM) under several practical assumptions. Our multivariate normal mixture model based approaches under MRF is applied to impute the missing pixel values of 3-variate (R, G, B) color image, providing a technique to smooth the imputed values.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1853-1855
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• 2005

본 논문에서는 카메라폰용 광학줌(Optical zooming)과 자동초점조절장치(Auto Focusing, AF)에 쓰일 초음파모터를 제작하였다. 초음파모터의 제작 및 시뮬레이션은 유한요소해석 프로그램인 ATILA 5.2.1(Magsoft)를 사용하여 디자인설계에 따른 구동특성을 고찰하였고 세자된 초음파모터는 한쪽 면이 없는 사자형의 탄성체를 제작하였으며 탄성체의 양쪽 다리에 각각 압전체를 부착하였다. 또한 압전세라믹의 조성은 $0.9Pb(Zr_{0.51}Ti_{0.49})O_3$-$0.1Pb(Mn_{1/3}Nb_{1/3}Sb_{1/3})O_3$의 조성으로 설계하였고 시편의 제조는 7-layer로 적층하였다. 제작된 압전세라믹의 치수는 $6*2*0.35mm^3$ (길이*폭*두께)로 제작하였다. 또한 탄성체의 외형치수는 $10*10*2mm^3$ 제작하였으며 두께를 각각 0.3[mm], 0.5[mm], 0.8[mm]으로 변화시키며 제작하였다. 두께가 0.8[mm]인 경우 공진주파수 60.5[kHz]를 나타내었으며 초음파모터의 압전세라믹에 인가전압이 증가함에 따라 회전속도와 모터에 흐르는 전류는 증가하였다. 인가전압이 40[Vpp], 공진주파수는 60.5[kHz]일때 무게추를 달고 그때의 토크 및 효율을 측정하였다. 회전 속도는 토크가 증가함에 따라 거의 선형적으로 감소하였으며 효율은 토크에 따라 증가하다가 토크가 약 20(mNmm)일 때 약 28[%]로 최대치를 나타내었다.

• Applied Microscopy
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• v.36 no.spc1
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• pp.1-7
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• 2006

The three-dimensional structure of an inorganic crystal, $SmZn_{0.67}Sb_2$ (space group $P4/nmm,\;a=4.30(3){\AA}\;and\;c= 10.27(1){\AA}$), was refined by electron crystallography utilizing high voltage electron microscopy (HVEM). Effects of instrumental resolution, image quality, beam damage and specimen tilting on the structure refinement have been evaluated. The instrumental resolution and image quality were the most important factors on the final results in the structure refinement, while the beam damage and specimen tilting effects could be experimentally minimized or controlled. The average phase errors $({\Phi}_{res})$ for the [001], [100] and [110] HVEM images of $SmZn_{0.67}Sb_2$ were $10.1^{\circ},\;9.6^{\circ}\;and\;6.8^{\circ}$, respectively. The atomic coordinates of $SmZn_{0.67}Sb_2$ were consistent within $0.0013{\AA}{\sim}0.0088{\AA}$, compared to the X-ray crystallography data for the same sample.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.1
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• pp.23-37
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• 1991

The understanding the natureof occlusal tooth contacts of natural dentition is important for correct diagnosis and treatment of diseases developed in stomatognatic system. Several investigator have studied the distribution of tooth contacts in maximum intercuspation and have reported contact locations with respect to the tooth position. Many methods have been clinically applied for the occlusal analysis in the intercuspal position. However, there are few quantative methods. This study analyzed the new software version of the T-Scan system to record and analyze occlusal contact balance in the anterior-posterior and right-left directions. Six time moment statistics and five moment statistics were calculated in the midsagittal and the incisal axes of the occlusal plane. In the present study, informed consent was obtained from 100 subjects with natural dentitions. The results were as follows ; 1. The mean of the dental arch length & width were 48.78, 65.32mm in whole population, 49.09mm, 65.50mm in males, 48.78mm, 64.63mm in females, respectively. 2. The mean of TLR & PLR were 0.193mm(left), 0.311mm(left), respectively. Therefore, the distribution of tooth contacts was bilaterally symmetric. 3. The mean of TFB & PFB were 29.168mm, 29.055mm, and that of LFB & RFB were 29.627mm, 29.587mm, respectively, and the qualitative center of occlusal contacts was the firtst molar. 4. The mean of LL & RL were 31.666mm, 31.377mm, respectively, and the quantitative center of occlusal force was the first molar. 5. The mean of LF & RF were 60.237N, 59.276N, respectively and Left-right moment was 72.491Nmm. Therfore, the distribution of occlusal force was bilaterally balanced.