• Title/Summary/Keyword: The Masking Method

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Retrieval of Aerosol Optical Depth with High Spatial Resolution using GOCI Data (GOCI 자료를 이용한 고해상도 에어로졸 광학 깊이 산출)

  • Lee, Seoyoung;Choi, Myungje;Kim, Jhoon;Kim, Mijin;Lim, Hyunkwang
    • Korean Journal of Remote Sensing
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    • v.33 no.6_1
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    • pp.961-970
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    • 2017
  • Despite of large demand for high spatial resolution products of aerosol properties from satellite remote sensing, it has been very difficult due to the weak signal by a single pixel and higher noise from clouds. In this study, aerosol retrieval algorithm with the high spatial resolution ($500m{\times}500m$) was developed using Geostationary Ocean Color Imager (GOCI) data during the Korea-US Air Quality (KORUS-AQ) period in May-June, 2016.Currently, conventional GOCI Yonsei aerosol retrieval(YAER) algorithm provides $6km{\times}6km$ spatial resolution product. The algorithm was tested for its best possible resolution of 500 m product based on GOCI YAER version 2 algorithm. With the new additional cloud masking, aerosol optical depth (AOD) is retrieved using the inversion method, aerosol model, and lookup table as in the GOCI YAER algorithm. In some cases, 500 m AOD shows consistent horizontal distribution and magnitude of AOD compared to the 6 km AOD. However, the 500 m AOD has more retrieved pixels than 6 km AOD because of its higher spatial resolution. As a result, the 500 m AOD exists around small clouds and shows finer features of AOD. To validate the accuracy of 500 m AOD, we used dataset from ground-based Aerosol Robotic Network (AERONET) sunphotometer over Korea. Even with the spatial resolution of 500 m, 500 m AOD shows the correlation coefficient of 0.76 against AERONET, and the ratio within Expected Error (EE) of 51.1%, which are comparable to the results of 6 km AOD.

Gate-Level Conversion Methods between Boolean and Arithmetic Masks (불 마스크와 산술 마스크에 대한 게이트 레벨 변환기법)

  • Baek, Yoo-Jin
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.46 no.11
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    • pp.8-15
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    • 2009
  • Side-channel attacks including the differential power analysis attack are often more powerful than classical cryptanalysis and have to be seriously considered by cryptographic algorithm's implementers. Various countermeasures have been proposed against such attacks. In this paper, we deal with the masking method, which is known to be a very effective countermeasure against the differential power analysis attack and propose new gate-level conversion methods between Boolean and arithmetic masks. The new methods require only 6n-5 XOR and 2n-2 AND gates with 3n-2 gate delay for converting n-bit masks. The basic idea of the proposed methods is that the carry and the sum bits in the ripple adder are manipulated in a way that the adversary cannot detect the relation between these bits and the original raw data. Since the proposed methods use only bitwise operations, they are especially useful for DPA-securely implementing cryptographic algorithms in hardware which use both Boolean and arithmetic operations. For example, we applied them to securely implement the block encryption algorithm SEED in hardware and present its detailed implementation result.

The Ability of Auditory Stimuli to Mask Siren Sounds in a Vehicle Graphic Simulator (자동차 그래픽 시뮬레이터에서 사이렌 소리 자극에 따른 청각 자극의 마스킹 효과)

  • Park, Jung-Sun;Kim, Gyu-Beom;Jo, Hyeong-Seok;Kim, Gyeong-Rae;Kim, Jun-Hyeong;Min, Byeong-Chan
    • Science of Emotion and Sensibility
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    • v.22 no.3
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    • pp.47-54
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    • 2019
  • We examined previous studies of the correlation analysis of heart rate variability as a method to reduce the stress caused by outside noise during driving, and we investigated whether there are electrocardiographic changes when drivers play music, which provides a stable sound source amid the noise. Because the number of cars increases every year, drivers and passengers show an increase in stress caused by outside noise. The stress from outside noise while a person is driving can cause several disorders, such as anxiety, immunosuppression, depression, and heart disease. Subjects in this study operated a vehicle simulator to reduce the stress from outside noise and were given different auditory stimuli, and we studied the drivers' responses to the stimuli. Repeated-measures analysis of variance revealed a significant differences between subjects exposed to different auditory stimuli (ρ < 0.05). Through post hoc analyses, we examined these differences. We found significant differences between factor 1 (stability) and factor 2 (simulation driving), between factor 1 (stability) and factor 3 (driving + police siren), and between factor 1 (stability) and factor 4 (driving + police siren + music). In addition, the factor that produced the highest level of sympathetic nervous system activity was factor 4 (driving + police siren + music), followed by factor 3 (driving + police siren), factor 2 (driving), and factor 1 (stability). In conclusion, even when a police siren was heard during driving, there were no significant differences on electrocardiograms (ECGs). In addition, even when the siren was heard over the music, there was no difference on the ECGs (ρ < 0.01). In future studies, investigators should determine which types of music help stabilize the heart rate during driving.

Automatic Detection Approach of Ship using RADARSAT-1 Synthetic Aperture Radar

  • Yang, Chan-Su
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.14 no.2
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    • pp.163-168
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    • 2008
  • Ship detection from satellite remote sensing is a crucial application for global monitoring for the purpose of protecting the marine environment and ensuring marine security. It permits to monitor sea traffic including fisheries, and to associate ships with oil discharge. An automatic ship detection approach for RADARSAT Fine Synthetic Aperture Radar (SAR) image is described and assessed using in situ ship validation information collected during field experiments conducted on August 6, 2004. Ship detection algorithms developed here consist of five stages: calibration, land masking, prescreening, point positioning, and discrimination. The fine image was acquired of Ulsan Port, located in southeast Korea, and during the acquisition, wind speeds between 0 m/s and 0.4 m/s were reported. The detection approach is applied to anchoring ships in the anchorage area of the port and its results are compared with validation data based on Vessel Traffic Service (VTS) radar. Our analysis for anchoring ships, above 68 m in length (LOA), indicates a 100% ship detection rate for the RADARSAT single beam mode. It is shown that the ship detection performance of SAR for smaller ships like barge could be higher than the land-based radar. The proposed method is also applied to estimate the ship's dimensions of length and breadth from SAR radar cross section(RCS), but those values were comparatively higher than the actual sizes because of layover and shadow effects of SAR.

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An Electrical Resistivity Survey for the Characterization of Alluvial Layers at Groundwater Artificial Recharge Sites (지하수 인공함양 지역 충적층 특성 평가를 위한 전기비저항탐사)

  • Won, Byeongho;Shin, Jehyun;Hwang, Seho;Hamm, Se-Yeong
    • Geophysics and Geophysical Exploration
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    • v.16 no.3
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    • pp.154-162
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    • 2013
  • Vertical electrical sounding and 2D electrical resistivity survey were applied for evaluating the characteristics of alluvial layers at a groundwater artificial recharge site. The fine particles in alluvial layer, main target layer of groundwater artificial recharge, may cause clogging phenomena. In this case, electrical resistivity method is an effective technique to verify the spatial distribution of low-resistivity layers, such as saturated silts and clays. On the other hand, much attention should be paid to interpret the resistivity data in unconsolidated layers, because thick clayey overburden sometimes produces a masking effect on underlying interbedded resistive sands and gravels. Considering these points, we designed 35 points arranged in a grid form for vertical electrical sounding and 10 lines for 2D electrical resistivity survey, and concentrated our effort on enhancing the vertical and horizontal resolution of resistivity images. According to the results, 15 meters thick layers consisting of sands and gravels are located in 30 meters below ground. And the spatial distribution of silts and clays are mapped, which may cause clogging. Consequently, this approach can contribute to design and determine the location and depth of injection and observation wells for groundwater artificial recharge.

MILP-Aided Division Property and Integral Attack on Lightweight Block Cipher PIPO (경량 블록 암호 PIPO의 MILP-Aided 디비전 프로퍼티 분석 및 인테그랄 공격)

  • Kim, Jeseong;Kim, Seonggyeom;Kim, Sunyeop;Hong, Deukjo;Sung, Jaechul;Hong, Seokhie
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.31 no.5
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    • pp.875-888
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    • 2021
  • In this paper, we search integral distinguishers of lightweight block cipher PIPO and propose a key recovery attack on 8-round PIPO-64/128 with the obtained 6-round distinguishers. The lightweight block cipher PIPO proposed in ICISC 2020 is designed to provide the efficient implementation of high-order masking for side-channel attack resistance. In the proposal, various attacks such as differential and linear cryptanalyses were applied to show the sufficient security strength. However, the designers leave integral attack to be conducted and only show that it is unlikely for PIPO to have integral distinguishers longer than 5-round PIPO without further analysis on Division Property. In this paper, we search integral distinguishers of PIPO using a MILP-aided Division Property search method. Our search can show that there exist 6-round integral distinguishers, which is different from what the designers insist. We also consider linear operation on input and output of distinguisher, respectively, and manage to obtain totally 136 6-round integral distinguishers. Finally, we present an 8-round PIPO-64/128 key recovery attack with time complexity 2124.5849 and memory complexity of 293 with four 6-round integral distinguishers among the entire obtained distinguishers.

Analysis of Volatile Flavor Components from Perilla frutescens var. acuta and Sensory Evaluation as Natural Spice (소엽의 휘발성 향미성분 분석 및 향신료로서의 관능적 평가)

  • 정미숙;이미순
    • Korean journal of food and cookery science
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    • v.16 no.3
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    • pp.221-225
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    • 2000
  • This study was conducted to investigate the usefulness of Perilla frutescens var. acuta as a natural spice. Volatile flavor components of dried Perilla frutescens var. acuta were extracted by supercritical fluid extraction method using diethyl ether as solvent. Essential oils were analyzed by gas chromatography (GC) and combined gas chromatography-mass spectrometry (GC-MS). Identification of volatile flavor components was based on the RI of GC and mass spectrum of GC-MS. A total of 24 components, including 4 hydrocarbons, 3 aldehydes, 8 alcohols, 4 esters, 3 acids and 2 miscellaneous components were identified in the essential oils. L-Perillaldehyde was found to be the major volatile flavor component of dried Perilla frutescens var. acuta. The masking effects of Perilla frutescens var. acuta on meaty and fishy flavor were measured by sensory evaluation. Meaty flavor was significantly reduced with the addition of 0.05%, 0.1%, and 0.2% Perilla frutescens var. acuta. The addition of 0.1% and 0.2% powdered Perilla frutescens var. acuta also reduced the fishy flavor of mackerel.

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Analysis of Volatile Flavor Components from Zanthoxylum schinifolium and Sensory Evaluation as Natural Spice (산초의 휘발성 향미성분 분석 및 향신료로서의 관능적 평가)

  • 이미순;정미숙
    • Korean journal of food and cookery science
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    • v.16 no.3
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    • pp.216-220
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    • 2000
  • Volatile flavor components in the fruits of dried Zanthoxylum schinifolium were extracted by supercritical fluid extraction method using diethyl ether as solvent. Essential oils were analyzed by gas chromatography (GC) and combined gas chromatography-mass spectrometry (GC-MS). Identification of volatile flavor components was based on the RI of GC and mass spectrum of GC-MS. A total of 30 components, including 6 hydrocarbons, 4 aldehydes, 8 alcohols, 5 esters, 4 acids and 3 miscellaneous components were identified in the essential oils. Geranyl acetate, ${\beta}$-phellandrene, D-limonene and citronellal were found to be major volatile flavor components in fruits of dried Zanthoxylum schinifolium. The masking effects of Zanthoxylum schinifolium on meaty and fishy flavor were measured by sensory evaluation to investigate the usefulness of Zanthoxylum schinifolium as a natural spice. Meaty flavor was significantly reduced with the addition of 0.05% and 0.1% Zanthoxylum schinifolium. And the addition of 0.l% powdered Zanthoxylum schinifolium also reduced the fishy flavor of mackerel.

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Studies on the Sorption Behavior of Some Metal Ions using XAD-16-Chromotropic Acid Chelating Resin (XAD-16-Chromotropic Acid 킬레이트 수지를 이용한 몇 가지 금속이온의 흡착거동에 관한 연구)

  • Lee, Won;Kim, Mi-Kyoung;Kim, In-Whan;Kim, Jun-Yong;Kim, Jung-Sook
    • Analytical Science and Technology
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    • v.17 no.6
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    • pp.454-463
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    • 2004
  • The sorption behavior of some metal ions on XAD-16-CTA chelating resin was investigated by batch method. The sorption of chelating resin was highly selective for Hf(IV), Zr(IV) and Th(IV) at pH 3.0 ~ 6.0 and the maximum sorption capacity of Zr(IV) ion was 0.81 mmol/g. It was successfully applied to the separation of several rare metal ions from mixed metal solutions by using CDTA, EDTA, NTA and $NH_4F$ as masking agent. The elution order of metal ions obtained from breakthrough capacity and the overall capacity at pH 4.0 was Zr(IV)>Th(IV)>Hf(IV)>U(VI)>Cu(II)>In(III)>Pb(II). Desorption characteristics for metal ions was investigated with desorption agents such as HCl, $HNO_3$, $HClO_4$. 2 M HCl showed high desorption efficiency. Th(IV) ion can be successfully separated from mixed metal ions by using XAD-16-CTA cheating resin.

A Clinical Study of Tinnitus (耳鳴에 관한 임상적 연구)

  • Choi, In-Hwa
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.14 no.2
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    • pp.134-145
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    • 2001
  • Introduction: Noises in the ear, whether real or imagined, are called tinnitus. Subjective causes of tinnitus(which is heard only by the patient) are extremely common and the majority of them are treated conservatively. For certain individuals their tinnitus is a major handicap; for others a trivial concern. The most common from of subjective tinnitus is a rushing, hissing or buzzing noise; it is frequently associated with sensorineural heanng loss. The patient may be unaware of the hearing loss, especially if it is a high frequency deficit of moderate severity. The character of the tinnitus may give a clue to the etiology. But the patient often has difficulty in explaining his/her tinnitus in absolute terms, as they have no other tinnitus with which to compare it but their own Tinnitus, like pain, is a subjective state and trying to objectively assess the severity is problematic. Audiological techniques to match subjective loudness to machine-produced noise may offer some help, in that sound intensity matches can bear little correspondence to subjective complaint. In spite of many studies, most patients presently seen complaining of tinnitus are told by their doctors that there is no treatment and that they will have to learn to live with this symptom. Objectives: To perform a clinical analysis of tinnitus and estimate the efficacy of Oriental Medical treatment according to the Byeonjeung(辨證). Subject: We studied 34 patients with complaints of tinnitus who had visited Pundang Cha Oriental Medicine Hospital Department of Otorhinolaryngology from March 1998 to February 2000. All of them had been treated 2 or 3 times a week with acupuncture treatment and had taken herbs according to the Byeonjeung(辨證) method. It was therefore possible for me to know whether their symptoms improved or not. Parameters Observed and Method: We treated them with acupuncture & herb-medication. Sometimes we gave them moxibustion or negative therapy with bloodletting at the acupuncture points(耳門, 聽宮, 聽會). Parameters Observed 1) Distribution of age & sex 2) Chief complaints 3) The sites of tinnitus 4) The quality of tinnitu 5) The duration of disease 6) The problem induced tinnitus 7) Factors increasing disease severity 8) The classification of the Byeonjeung(辨證) 9) The efficacy of treatments Results: 1. Age and sex distribution: The most common occurrence was found in males in their twenties: 6 males($17.7\%$), and in females in their thirties and over sixty: 8 females($23.5\%$). Total patient numbers for men and women were 20 men($58.8\%$), 14 women ($41.2\%$). 2. The most frequent major complaints were hearing disturbances related to tinnitus; and dizziness with tinnitus; each comprising 10 cases($29.4\%$). There were also 7 patients($20.6\%$) with only tinnitus. 3. Tinnitus sites: 13($38.2\%$) said that they felt tinnitus in both ears, equally. In the right ear, 9($26.5\%$), in the left, 6($17.7\%$). 4. The most frequent descriptive symptoms of tinnitus were: humming, hissing, buzzing etc. 5. The duration of disease. 14cases($41.2\%$) had a duration of less than 1 year. 6. 15cases($44.1\%$) complained that it was hard to watch TV or make a phone call because of tinnitus. 10 cases($29.4\%$) complained about depression. 7. Factors increasing severity of tinnitus: ⅰ) fatigue: 18cases($52.9\%$) ⅱ) stress/ tension: 10 cases($29.4\%$) ⅲ) alcohol and tobacco: 5cases($l4.7\%$) 8. Classification through Byeonjeung : ⅰ) 19 cases($55.9\%$) were classified as showing Deficiency syndrome. ⅱ) 15 cases($44.l\%$) were classified as showing Excess syndrome. The deficiency of Qi was 7($20.6\%$), deficiency of Xue, 8($23.5\%$) and insufficiency of the Kidney Yin & Yang, 4($11.8\%$). The flare of Liver fire was 8($23.5\%$) and phlegm-fire, 7($20.6\%$), 9. The efficacy of treatments showed: an improvement in 17cases($50.0\%$); no real improvement or changes in 13 cases($38.2\%$); and some worsening in 4 cases($11.8\%$). In the group with deficiency in Qi, 4($57.1\%$) improved, 1($14.3\%$) showed no change and 2($28.6\%$) were aggravated. In the cases of deficiency in Xue, 6($75.0\%$) improved, 2($25.0\%$) showed no change. In the cases of insufficiency of Kidney Yin & Yang, 3($75.0\%$) showed no change and 1($25.0\%$) were aggravated. In the group of flare of Liver fire, 4($50.0\%$) improved, 3($37.5\%$) no change and 1($12.5\%$) were aggravated. In the cases of phlegm-fire, 3($42.9\%$) improved, 4($57.1\%$) showed no change. Conclusion: We would recommend that any further studies of tinnitus utilize trial treatments of longer than 2 months duration, as any positive effects observed in our study showed that improvement occurred fairly slowly. And we suggest that this study could be utilized as a reference for clinical Oriental Medical treatment of tinnitus. If we try to apply music or sound therapy treatment properly combined with ours, we expect it to provide psycological stability in addition to inducing masking effects, even though it may not directly decrease or completely remove tinnitus.

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