• Title/Summary/Keyword: 510(k)

Search Result 1,196, Processing Time 0.029 seconds

Review on Self-embedding Fragile Watermarking for Image Authentication and Self-recovery

  • Wang, Chengyou;Zhang, Heng;Zhou, Xiao
    • Journal of Information Processing Systems
    • /
    • v.14 no.2
    • /
    • pp.510-522
    • /
    • 2018
  • As the major source of information, digital images play an indispensable role in our lives. However, with the development of image processing techniques, people can optionally retouch or even forge an image by using image processing software. Therefore, the authenticity and integrity of digital images are facing severe challenge. To resolve this issue, the fragile watermarking schemes for image authentication have been proposed. According to different purposes, the fragile watermarking can be divided into two categories: fragile watermarking for tamper localization and fragile watermarking with recovery ability. The fragile watermarking for image tamper localization can only identify and locate the tampered regions, but it cannot further restore the modified regions. In some cases, image recovery for tampered regions is very essential. Generally, the fragile watermarking for image authentication and recovery includes three procedures: watermark generation and embedding, tamper localization, and image self-recovery. In this article, we make a review on self-embedding fragile watermarking methods. The basic model and the evaluation indexes of this watermarking scheme are presented in this paper. Some related works proposed in recent years and their advantages and disadvantages are described in detail to help the future research in this field. Based on the analysis, we give the future research prospects and suggestions in the end.

Modeling and Control of an Engine Mount Using ER Fluids and Piezoactuators (ER 유체와 압전작동기를 이용한 엔진마운트의 모델링 및 제어)

  • Choi, Seung-Hoon;Choi, Young-Tai;Choi, Seung-Bok
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.20 no.2
    • /
    • pp.500-510
    • /
    • 1996
  • This paper presents a new prototype of an engine mount for a passenger vehicle featuring ER(elector-rheological) fluids and piezoactuators. Conventional rubber mounts and various types of passive or semi-active hydraulic engine mounts have their own functional aims on the limited frequency band in the board engine operating frequency range. However, the proposed engine mount covers all frequency range of the engine operation. A mathematical model of the proposed engine mount is derived using the bond graph method which is inherently domain, the ER fluid is activated upon imposing electric field for vibration isolation while the piezoactuator. Computer control electric fluid for the ER fluid H.inf. cotrol technique is adopted for the piezoactuator. Computer simulation is undertaken in order to demonstrate isolation efficiency of the engine mount over wide operating frequency range.

Improvement of Image Compression Using Quantization Technique in Computed Tomography Images (CT영상에서 양자화기법을 이용한 영상압축의 개선)

  • Park, Jae-Hong;Yoo, Ju-Yeon;Park, Cheol-Woo
    • Journal of the Korean Society of Radiology
    • /
    • v.12 no.4
    • /
    • pp.505-510
    • /
    • 2018
  • In this study, we allocate bits by quantizing these fractal coefficients through a quantizer which can extract the probability distribution. In the coding process of IFS, a variable size block method is used to shorten the coding time and improve the compression ratio. In the future, it will be necessary to further improve the coding time and the compression rate while maintaining the best image quality in the fractal coding process.

Annual Runoff Loading of Nitrogen and Phosphorus from a Paddy Field

  • Han, Kang-Wan;Cho, Jae-Young;Choi, Jin-Kyu
    • Journal of Applied Biological Chemistry
    • /
    • v.42 no.1
    • /
    • pp.29-33
    • /
    • 1999
  • The present study examined annual runoff loading of nitrogen and phosphorus in the paddy field from 1 May, 1997 to 30 April, 1998. In the investigated area, the amount of rainfall was 1,095.6 mm and 414.6 mm during cropping season and non-cropping season. The annual rainfall was 1,510.2 mm. The total amount of runoff water was 1,043.2 mm and 281.0mm during cropping season and non-cropping season, and the added total amount of runoff water during two seasons was 1,324.2 mm. The runoff loading of nutrients caused by runoff water was measured as follows. The total-N was 149.23 and $8.67kg\;ha^{-1}$ (total amount=$157.90kg^{-1}ha^{-1}yr^{-1}$), the ammonia-N 102.98 and $4.44kg\;ha^{-1}$ ($107.42kg^{-1}ha^{-1}yr^{-1}$), the nitrate-N 28.45 and $1.23kg\;ha^{-1}$ ($29.68kg^{-1}ha^{-1}yr^{-1}$), the total-P 4.16 and $0.38kg\;ha^{-1}$ ($4.54kg^{-1}ha^{-1}yr^{-1}$) during cropping and non-cropping season respectively. When the loss ratio was calculated based on amounts of chemical fertilizer, about 68.6% of nitrogen and 16.7% of phosphorus was lost by runoff from applied fertilizer amount.

  • PDF

Social Perceptions of Breast Cancer by Women Still Undergoing or Having Completed Therapy: a Qualitative Study

  • Mermer, Gulengul;Nazli, Aylin;Ceber, Esin
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.17 no.2
    • /
    • pp.503-510
    • /
    • 2016
  • Background: Diagnosis and treatment of breast cancer is a crisis situation which effects women's lives physically, socially and spiritually. Investigating women's perceptions of this disease is crucially important for treatment decisions. We therefore determined social perceptions and interpretations of women diagnosed with breast cancer during therapy and in the post-treatment period. Materials and Methods: In the study, focus group and in-depth interviews were made with women still undergoing or having completed breast cancer treatment. Some 25 women were included in the research. Content analysis was used in the analysis of the qualitative data obtained after the focus group and in-depth interviews. Results: Some of the women demonstrated positive perceptions towards accepting the disease, whereas others had emotions such as rebellion and anger. The loss of a breast is important with different interpretations. Conclusions: Women's acceptance or rebellion against the disease varies within their social interpretations after the treatment, as at the stage of diagnosis/treatment. All stages of breast cancer negatively affect the social life of the affected individual as much as her body. Nurses assume crucial roles in coping with these negative effects. Thus, it is necessary to know, and sociologically interpret, what is indicated by the information on what the negative effects concerning the disease are and how they are interpreted.

Implementation of Fast Inverse Quantization and Inverse Transform Module for VC-1 (VC-1용 고속 역양자화 및 역변환 모듈 구현)

  • Kim, Kyung Hyun;Song, Hyung Don;Sohn, Seung Il
    • Proceedings of the Korea Contents Association Conference
    • /
    • 2007.11a
    • /
    • pp.837-841
    • /
    • 2007
  • 최근 영상을 중심으로 여러 형태의 정보를 결합하여 저장하거나 전송하는 멀티미디어가 많은 관심을 받고 있다. 현재 카메라와 관련된 동영상 캡처기술은 Motion JPEG이 주류를 이루고 있으며, 텔레비전, DMB 등의 방송 분야 및 DVD, VCR 분야에서는 MPEG-2, MPEG-4, H.264 및 WMV9 등의 압축 코덱이 채용되고 사용되고 있다. 그러나 이러한 다양한 영상 표준방식은 디코딩시 호환성 문제가 발생하게 되고 이에 따라 통합 코덱 연구가 필요하다. 이에 본 논문은 일반적 스텝 양자화외에 데드존 양자화를 사용하고 "$4{\times}4$", "$4{\times}8$", "$8{\times}4$", "$8{\times}8$"의 다양한 블록크기의 변환을 지원하는 VC-1을 기반으로 한 ITIQ C언어를 통해 시뮬레이션하고 최적화된 결과를 VHDL로 구현하여 향후 통합코덱 연구에 응용 가능하도록 연구 및 분석평가 하였다. 설계결과 4:2:0의 YCbCr포맷의 최초 $16{\times}16$블록을 복원하는데 483~510클록이 소요되었고 Xilinx XCVPC100 FF1696-6 환경에서 93,128개의 게이트 수와 71.469MHz의 동작속도를 나타내었다. 이는 640*480 크기의 컬러영상을 디코딩 하는데 프레임 당 최대 0.0074초가 소요됨을 의미하며 초당 30프레임의 영상에서도 0.222초면 디코딩이 가능한 결과이다.

  • PDF

An Energy-Efficient Clustering Algorithm consider Minimum-hop in Hierarchical Sensor Network (계층구조 센서 네트워크에서 Minimun-hop 을 고려한 클러스터 구성 알고리즘)

  • Kim, Yong;Lee, Doo-Wan;Jang, Kyung-Sik
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
    • /
    • 2010.10a
    • /
    • pp.510-513
    • /
    • 2010
  • In hierarchical wireless sensor network, Sensor nodes forming a cluster with a hierarchy. And there are being study for balanced energy consumption between cluster nodes. When forming network routing path, if there are configured incorrectly then it can be wasting energy. In this paper to solve these problem, We propose that it can consider sensor's communication range to create minimum hop layer when cluster heads configure routing path.

  • PDF

Analysis of the Effects of an Educational Program regarding Food Safety for Children (아동의 식품 안전 교육 프로그램에 대한 효과 분석)

  • Kim, Mee-Ra;Jeon, Mi-Kyung;Kim, Hyo-Chung
    • Journal of the Korean Home Economics Association
    • /
    • v.44 no.6 s.220
    • /
    • pp.113-120
    • /
    • 2006
  • The purpose of this study was to examine the effects of an educational program regarding food safety for children. The data were collected from the results of a self-administered questionnaire that was given to 510 6th grade elementary school students in the Youngnam region who had undergone a food safety education program. The results of this study were as follows. First, the educational need for food safety was high in each food safety category, with the educational need for prevention against foodborne illness being the highest of the 10 categories. On the basis of the study results, educational materials were developed which targeted personal hygiene, food labeling, food purchase, food washing, food storage, cooking, foodborne illness prevention, food additives, endocrine disruptors, and illegal foods. Additionally, about 37% of the respondents aswered that they preferred the food safety education to be conducted at home. Second, the food safety education significantly improved the levels of knowledge and behavior of children toward food safety. These results imply that food safety education that addresses the concerns of children and their parents' is needed to improve the level of knowledge and behavior toward food safety.

A Study on the Egg Deposition and the Development of Pettancylus nipponicus (Basommatophora: Ferrissidae) (담수삿갓조개(Pettancylus nipponicus)의 산란(産卵)과 발생(發生)에 관(關)한 연구(硏究))

  • Kwon, Oh-Kil;Lee, Jun-Sang;Park, Gap-Man
    • The Korean Journal of Malacology
    • /
    • v.2 no.1
    • /
    • pp.10-12
    • /
    • 1986
  • Pettancylus nipponicus (freshwater limpet) collected from the Lake Choon Cheon were cultrued in aquarium and studied in the respects of an egg deposition and the developmental characters of cleavage. The species were collected only in the Lake Uiam and Choon Cheon and easily sampled on the debris like vinyls and cans. Those smooth surfaces were suitalble substrata for attaching. P. nipponicus, about 4 mm in adult, deposited an egg in one calcareous egg-capsule on the aquarium walls, while many eggs are surrounded in a jelly-like egg-envelope in the most gastropods. And another special features was that an egg-capsule was consisted of two valves and the suture was opended as hatching. A diameter of its egg was $55{{\mu}m}$ and the length of an egg capsule was $620{{\mu}m}$ and $510{{\mu}m}$ in long and short diameter, respectively. It took about 8 hours from beginning cleavage to 16-cell stage and about one year to become an adult.

  • PDF

Problems and improvement methods of passive treatment systems for acid mine drainage in Korea

  • Ji, Sang-Woo;Ko, Ju-In;Kim, Sun-Joon
    • 한국지구물리탐사학회:학술대회논문집
    • /
    • 2003.11a
    • /
    • pp.504-510
    • /
    • 2003
  • This study has been carried out to evaluate the passive treatment systems for acid mine drainage in Korea and to suggest, if possible, the method for the improvement. 35 passive treatment systems in 27 mines have been constructed since 1996. SAPS, being the main process, was combined with more than one of processes such as anaerobic wetland, aerobic wetland, and oxidation pond for the construction of passive treatment system. Problems observed during the operation include the poor sulfate removal ratio, overflow, leakage, unusabless of the whole system, and inefficiency. The reasons of the poor sulfate removal ratio are believed that the low temperature during the winter prohibits the SRB activity and HRT for bacterial sulfate reduction is insufficient. An alternative method In Adit Sulfate Reducing System which enables to keep the temperature constant at about $15^{\circ}C$ was suggested. IASRS is the methods of placing the SAPS inside the adit, which enables the temperature around the system constant can be maintained. The experiments using the laboratory scaled model systems made up of four sections showed high efficiencies in pH control and metal removal ratios, but showed still low sulfate removal ratio of about $23\%$ also with high COD at the beginning of the operation.

  • PDF