• 제목/요약/키워드: Randomized Key

검색결과 187건 처리시간 0.025초

데이터 매트릭스와 비밀 키를 이용한 하이브리드 워터마킹 방법 (Hybrid Watermarking Scheme using a Data Matrix and Secret Key)

  • 전성구;김일환
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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    • pp.144-146
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    • 2006
  • The Data Matrix of two-dimensional bar codes is a new technology capable of holding relatively large amounts of data compared to the conventional one-dimensional bar code which is just a key that can access detailed information to the host computer database. A secret key is used to prevent a watermark from malicious attacks. We encoded copyright information into a Data Matrix bar code for encoding process and it was spread a pseudo random pattern using owner key. We embedded a randomized watermark into the image using watermark's embedding position, pattern generated with a secret key. The experimental results have shown that the proposed scheme has good quality and is very robust to various attacks, such as JPEG compression and noise. Also the performance of the proposed scheme is verified by comparing the copyright information with the information which is extracted from a bar code scantier.

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전력분석 공격에 대응하는 타원곡선 상의 결합 난수 스칼라 곱셈 알고리즘 (A Combined Random Scalar Multiplication Algorithm Resistant to Power Analysis on Elliptic Curves)

  • 정석원
    • 사물인터넷융복합논문지
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    • 제6권2호
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    • pp.25-29
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    • 2020
  • 타원곡선 암호 알고리즘은 RSA 공개키 알고리즘에 비해 짧은 키의 길이와 적은 통신 부하 때문에 IoT 환경에서 인증용으로 많이 사용되고 있다. 타원곡선 암호 알고리즘의 핵심연산인 스칼라 곱셈이 안전하게 구현되지 않으면, 공격자가 단순 전력분석이나 차분 전력분석을 사용하여 비밀 키를 찾을 수 있다. 본 논문에서는 스칼라 난수화와 타원곡선점 가리기를 함께 적용하고, 연산의 효율성이 크게 떨어지지 않으며 전력분석 공격법에 대응하는 결합 난수 타원곡선 스칼라 알고리즘을 제안한다. 난수 r과 랜덤 타원곡선 점 R에 대해 변형된 Shamir의 두 배 사다리 알고리즘을 사용하여 타원곡선 스칼라 곱셈 kP = u(P+R)-vR을 계산한다. 여기에서 위수 n=2l±c일 때, 2lP=∓cP를 이용하여 l+20 비트 정도의 u≡rn+k(modn)과 ν≡rn-k(modn)를 구한다.

Effectiveness of alendronate as an adjunct to scaling and root planing in the treatment of periodontitis: a meta-analysis of randomized controlled clinical trials

  • Chen, Jin;Chen, Qian;Hu, Bo;Wang, Yunji;Song, Jinlin
    • Journal of Periodontal and Implant Science
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    • 제46권6호
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    • pp.382-395
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    • 2016
  • Purpose: Alendronate has been proposed as a local and systemic drug treatment used as an adjunct to scaling and root planing (SRP) for the treatment of periodontitis. However, its effectiveness has yet to be conclusively established. The purpose of the present meta-analysis was to assess the effectiveness of SRP with alendronate on periodontitis compared to SRP alone. Methods: Five electronic databases were used by 2 independent reviewers to identify relevant articles from the earliest records up to September 2016. Randomized controlled trials (RCTs) comparing SRP with alendronate to SRP with placebo in the treatment of periodontitis were included. The outcome measures were changes in bone defect fill, probing depth (PD), and clinical attachment level (CAL) from baseline to 6 months. A fixed-effect or random-effect model was used to pool the extracted data, as appropriate. Mean differences (MDs) with 95% confidence intervals (CIs) were calculated. Heterogeneity was assessed using the Cochrane ${\chi}^2$ and $I^2$ tests. Results: After the selection process, 8 articles were included in the meta-analysis. Compared with SRP alone, the adjunctive mean benefits of locally delivered alendronate were 38.25% for bone defect fill increase (95% CI=33.05%-43.45%; P<0.001; $I^2=94.0%$), 2.29 mm for PD reduction (95% CI=2.07-2.52 mm; P<0.001; $I^2=0.0%$) and 1.92 mm for CAL gain (95% CI=1.55-2.30 mm; P<0.001; $I^2=66.0%$). In addition, systemically administered alendronate with SRP significantly reduced PD by 0.36 mm (95% CI=0.18-0.55 mm; P<0.001; $I^2=0.0%$) and increased CAL by 0.39 mm (95% CI=0.11-0.68 mm; P=0.006; $I^2=6.0%$). Conclusions: The collective evidence regarding the adjunctive use of alendronate locally and systemically with SRP indicates that the combined treatment can improve the efficacy of non-surgical periodontal therapy on increasing CAL and bone defect fill and reducing PD. However, precautions must be exercised in interpreting these results, and multicenter studies evaluating this specific application should be carried out.

얼굴마비의 임상연구병행 경제성평가 프로토콜 개발을 위한 체계적 문헌고찰연구 (Systematic Review for the Development of the Clinical Study with Economical Assessment Protocol on Facial palsy)

  • 공나경;서은성;선지혜;김남권
    • 대한한의학회지
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    • 제38권1호
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    • pp.46-55
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    • 2017
  • Objectives: The aim of this study is reviewing the literature to extract the key parameter, study design, perspective, cost-effectiveness index and find the calibration parameter for the clinical study with economical evaluation protocol on facial palsy. Methods: Literature search is performed using PUBMED for literature published from January 2000 to December 2016. We included randomized controlled trials(RCTs) and modelling study with economic assessment in which human participated. Results: As a result of literature search, the 198 articles were found. After reviewing the title, abstract and full text, the 5 articles were selected. Selected articles are classified into 4 RCT studies dealing with quality of life and 1 CEA(cost-effectiveness analysis) study. Conclusions: We found reliable key parameters, calibration parameters and elements of economical assessment study, which might be necessary factors for developing research protocol of clinical trial with economic evaluation about facial palsy patients.

아토피 피부염의 임상연구병행 경제성평가 프로토콜 개발을 위한 체계적 문헌고찰연구 (Systematic Review for the Development of the Clinical Study with Economical Assessment Protocol on Atopic Dermatitis)

  • 권지예;선지혜;윤화정;김남권
    • 한방안이비인후피부과학회지
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    • 제30권1호
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    • pp.17-28
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    • 2017
  • Objectives : The aim of this study is reviewing the literature to extracting the key parameter and finding the calibration parameter for the clinical study with economical assessment protocol on atopic dermatitis. Methods : Literature search is performed using PUBMED for literature published from Janurary 2000 to December 2016. We included randomized controlled trials(RCTs) with economic assessment in which human participants. Results : Among the articles published from January 2000 to December 2016, The 1464 articles were found. After reviewing the title, abstract and full text, the five articles were selected. Selected articles are classified 3 CEA(cost effective analysis)study, 1 CMA(cost minimizing analysis)study and 1 cost analysis study. Conclusions : We found highly reliable key parameters and calibration parameters, which might be necessary factors for developing research protocol of economic evaluation alongside clinical trial about atopic dermatitis patients.

경혈경락 이론에 근거한 체외충격파 치료가 유착성 관절낭염에 미치는 영향: 무작위 대조 임상연구에 대한 체계적 문헌고찰과 메타분석 (Extracorporeal Shock Wave Therapy with Meridian and Acupoint Theory for Adhesive Capsulitis: A Systematic Review and Meta-analysis of Randomized Controlled Trials)

  • 한동훈;박인화;허인
    • 한방재활의학과학회지
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    • 제32권2호
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    • pp.55-63
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    • 2022
  • Objectives This review was conducted to evaluate effectiveness and safety of extracorporeal shock wave therapy (ESWT) with meridian and acupoint theory for adhesive capsulitis. Methods By December 2021, 11 electronic databases were reviewed with the key words 'extracorporeal shock wave' and '(acupuncture OR acupoint OR meridian)'. This key words was set up to increase the sensitivity of the search. After the search, adhesive capsulitis study was selected based on the title and abstract and then included after full-texts were read. Results Five randomized controlled trials were eligible in our inclusion criteria. The meta-analysis of 3 studies showed positive results for the using ESWT with meridian and acupoint theory for adhesive capsulitis compared with the control group on efficancy rate and range of shoulder flexion. Conclusions Some studies showed ESWT with meridian and acupoint theory were statistically effective to adhesive capsulitis. But the evidence is limited due to the defective design of the included randomized controlled trials (RCTs). So use of ESWT with meridian and acupoint theory for adhesive capsulitis has limited evidence. More well-designed RCTs are required to provide clearer evidence for this claim.

Effect and stability of miniscrew-assisted rapid palatal expansion: A systematic review and meta-analysis

  • Huang, Xinyi;Han, Yu;Yang, Shuangyan
    • 대한치과교정학회지
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    • 제52권5호
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    • pp.334-344
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    • 2022
  • Objective: This study aimed to systematically analyze the effect and stability of miniscrew-assisted rapid palatal expansion (MARPE) to provide a reference for the clinical treatment of patients with maxillary transverse deficiency (MTD). Methods: We searched PubMed, Science Direct, Web of Science, Embase, Cochrane Library, CNKI, and Wanfang Database for relevant studies published before February 18, 2021 and selected them according to the eligibility criteria. The Cochrane Handbook for Systematic Reviews (version 5.1.0) criteria were used for the quality assessment of randomized controlled trials, while the scoring protocol of the methodological index for non-randomized studies was used for non-randomized controlled trials. Statistical analysis was performed using the RevMan5.3 software. Results: All the included studies showed a relatively high success rate of expansion. The changes in both the intermolar and alveolar widths after MARPE were statistically significant. MARPE exhibited greater skeletal expansion effects than did conventional RPE. The midpalatal suture was opened in parallel after MARPE. A small amount of relapse was observed 1 year after expansion. MARPE caused tooth inclination and a decrease in alveolar height, but it was less significant than in conventional RPE. Conclusions: MARPE may be an effective treatment modality for patients with MTD. It causes great transverse skeletal expansion in late adolescence. In comparison to conventional RPE, MARPE has lower detrimental periodontal effects and has certain clinical advantages.

투렛장애 (Tourette syndrome)의 침 치료에 대한 중의학 임상 연구 고찰 (A Review of Clinical Researches for Acupuncture Treatment on Tourette Syndrome)

  • 김보람;최일신;김기봉;천진홍
    • 대한한방소아과학회지
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    • 제36권2호
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    • pp.13-25
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    • 2022
  • Objective This study aimed to analyze randomized controlled trials of the effect of acupuncture on Tourette syndrome and to evaluate the efficacy of the treatment. Methods Based on the China National Knowledge Infrastructure (CNKI) and Pubmed search with the key search terms of 'Tourette syndrome, acupuncture', dated from 2000 to 2021, ten randomized controlled trials were identified and analyzed for this study. Results 1. The most commonly used acupoints were Taechung (LR3), Sinmun (HT7), Hapgok (LI4), Pungji (GB20) and Backhoe (GV20). 2. The most commonly used meridians were Bladder Meridian, Stomach Meridian and Gallbladder Meridian. 3. Acupuncture treatment was found to be significantly more or equally effective than western medicine such as haloperidol and tiapride. Conclusions Based on the results of the randomized controlled trials analyzed in this study, acupuncture was found to be effective in the treatment of Tourette syndrome. However, more clinical studies are needed to prove the effectiveness of acupuncture in Tourette syndrome.

소아 주의력결핍 과잉행동장애 (ADHD)의 추나요법 효과에 대한 임상연구 고찰 - 중의학 무작위 대조군 임상연구를 중심으로 - (A Review of Clinical Studies for Tuina Treatment on Attention Deficit Hyperactivity Disorder (ADHD) - Focused on Chinese Randomized Controlled Trials -)

  • 이민영;류의성;최일신;김기봉;천진홍
    • 대한한방소아과학회지
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    • 제36권3호
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    • pp.63-74
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    • 2022
  • Objective This study aimed to analyze the efficacy and safety of Tuina therapy for attention-deficit hyperactivity disorder (ADHD) through a randomized controlled clinical study in China. Methods We used the China National Knowledge Infrastructure (CNKI) as a resource and conducted a search using key words: 'ADHD', '推拿'. Six randomized control studies were identified and analyzed in this study. Results 1. The Tuina treatment group showed significant changes compared to the control group. 2. The most commonly used meridians were Spleen meridian (脾經穴), Liver meridian (肝經穴), Errenshangma (二人上馬穴), Xiaotianxin (小天心), Qinghetianshu (清河天水), Kidney meridian (腎經穴). Conclusions The results of this study showed that Tuina therapy is effective for ADHD patients with ADHD. It can be used for future research on Tuina therapy for ADHD.

Secret-key-sharing Cryptosystem Using Optical Phase-shifting Digital Holography

  • Jeon, Seok Hee;Gil, Sang Keun
    • Current Optics and Photonics
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    • 제3권2호
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    • pp.119-127
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    • 2019
  • A new secret-key-sharing cryptosystem using optical phase-shifting digital holography is proposed. The proposed secret-key-sharing algorithm is based on the Diffie-Hellman key-exchange protocol, which is modified to an optical cipher system implemented by a two-step quadrature phase-shifting digital holographic encryption method using orthogonal polarization. Two unknown users' private keys are encrypted by two-step phase-shifting digital holography and are changed into three digital-hologram ciphers, which are stored by computer and are opened to a public communication network for secret-key-sharing. Two-step phase-shifting digital holograms are acquired by applying a phase step of 0 or ${\pi}/2$ in the reference beam's path. The encrypted digital hologram in the optical setup is a Fourier-transform hologram, and is recorded on CCDs with 256 quantized gray-level intensities. The digital hologram shows an analog-type noise-like randomized cipher with a two-dimensional array, which has a stronger security level than conventional electronic cryptography, due to the complexity of optical encryption, and protects against the possibility of a replay attack. Decryption with three encrypted digital holograms generates the same shared secret key for each user. Schematically, the proposed optical configuration has the advantage of producing a kind of double-key encryption, which can enhance security strength compared to the conventional Diffie-Hellman key-exchange protocol. Another advantage of the proposed secret-key-sharing cryptosystem is that it is free to change each user's private key in generating the public keys at any time. The proposed method is very effective cryptography when applied to a secret-key-exchange cryptosystem with high security strength.