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The Noise Level Assessment of Dental Equipment (치과 의료장비의 소음 수준 평가)

  • Lee, Jeong-Suk;Han, Ye-Seul;Cho, Young-Sik
    • Journal of dental hygiene science
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    • v.15 no.5
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    • pp.603-611
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    • 2015
  • This research is aimed at cutting off hearing loss and other harmful factors due to noise and providing basic material for noise reduction plan. As the research method, this research assessed noise by measuring acoustic pressure level and frequency in various situation of non-treatment and treatment. As the measurement result, average noise degree of high speed handpiece of non-treatment, ultrasonic waves scaler, and low speed handpiece showed 58~66 dB(A). Average noise degree of scaling of treatment, tooth elimination, and denture adjust showed 73~81 dB(A). The result is inferior to recognized standards of noise induced hearing loss. But the result of assessing this with (noise rating) NR curve was NR-73~78, which exceeded general workplace noise standard. This level can cause hearing loss when exposed to a long time. Therefore, treatment office noise during dental treatment can cause psychological and physical damage in dental clinic employees, and it is urgently required to establish systematic and active noise reduction plan.

Development of Web Application Based on N-screen for Play Activities of Children with Developmental Disorder (발달장애 아동의 놀이 활동을 위한 N-스크린 기반의 웹앱 개발)

  • Kang, Jung Bae;Kim, Jin Hee;Kim, Chang Geol;Song, Beong Seop
    • Journal of Korea Society of Industrial Information Systems
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    • v.18 no.4
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    • pp.1-8
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    • 2013
  • In the modern society, instructional methods using diverse media have appeared thanks to the development of Information & Communication Technology, and applicability of such instructional methods has been fully corroborated. However, customized contents allowing for disabled children's environment are still insufficient. Hence, this study produced educational contents of play activities for children with developmental disability, through applying N-screen technology, IT technology that can provide the same contents via a variety of digital media. The produced contents allow programs to be set up according to a child's individual characteristics and be carried out anywhere and anytime via an Internet-enabled digital device. Further, the developed contents were produced so that they could be accessed from a child's various environment (home, school, etc.) via a PC, a smart phone, a portable from a child's various environment (home, school, etc.) via a PC, a smart phone, a portable device, etc. and that the same educational program could be conducted in linkage at home, school, etc. Three children with Intellectual disability and autism spectrum disorder were applied to the manufactured content. As a result, Content interaction between interaction between teachers and students in play training could use as a medium.In addition, the children's ability to select the appropriate components and reinforcements, special education professionals have used the content of the interviews are helpful in mediation than the existing content.

A study of sound graphic equalizer configuration using photo image (이미지를 이용한 사운드 그래픽 이퀄라이저의 구성에 대한 연구)

  • Seo, June-Seok;Hong, Sung-Dae;Park, Jin-Wan
    • 한국HCI학회:학술대회논문집
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    • 2008.02b
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    • pp.430-435
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    • 2008
  • Thanks to the development of IT technology, there have been developed a variety of types of portable music players. IT technology didn't stop there, however. It has gone to developing GUIs (Graphic User Interfaces) to deliver more information to the user. As the function of GUIs has become important, the music players are being required to show characteristics of the sounds they output visually beyond just delivering the sounds through analyzing the information that the sounds contain. To visualize the information of sounds, that is to say, has become substantial. In this process, sound graphic equalizers have been developed in order. The object of this study is to produce a new sound graphic equalizer with new forms of expressing visual images of sounds besides the bar graphs, in which user feedback is possible. This study has devised a new sound visualization form in visually expressing the information of sounds by analyzing their characteristics. This new sound visualization provides a sound graphic equalizer with which the user can select images for the information of the sounds s/he listens. This study suggests a new alternative GUI with which the user can change the form of the outputted images in realtime as communicating with the player.

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Implementation of OpenVG on Embedded Systems (임베디드 시스템을 위한 OpenVG 구현)

  • Lee, Hwan-Yong;Baek, Nak-Hoon
    • Journal of Korea Multimedia Society
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    • v.12 no.3
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    • pp.335-344
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    • 2009
  • Embedded systems and web browsers have started to provide two-dimensional vector graphics features, to finally support scalability of graphics outputs, while traditional graphics systems have focused on the raster and bitmap operations. Nowadays, SVG and Flash are actively used while OpenVG from Khronos group plays the role of a de facto low-level API standard to support them. In this paper, we represent the design and implementation process and the final results of an OpenVG implementation, AlexVG. From its design stage, our implementation aims at the cooperation with SVG-Tiny, another de facto standard for embedded systems. Currently, our overall system provides not only the OpenVG core features but also variety of OpenVG application programs and SVG-Tiny media file playing capabilities. For the conformance with the standard specifications, our system completely passed the whole OpenVG conformance test suites and the graphics output portions of the SVG-Tiny conformance test suites. From the performance point of view, we focused on the efficiency and effectiveness especially on the mobile phones and embedded devices with limited resources. As the result, it showed impressive benchmarks on the small-scale CPU's such as ARM's, even without neither any other libraries nor acceleration hardware.

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Maximum Power Point Tracking Method Without Input side Voltage and current Sensor of DC-DC Converter for Thermoelectric Generation (열전발전을 위한 DC-DC Converter의 입력측 전압·전류 센서없는 최대전력점 추적방식)

  • Kim, Tae-Kyung;Park, Dae-Su;Oh, Sung-Chul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.3
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    • pp.569-575
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    • 2020
  • Recently, research on renewable energy technologies has come into the spotlight due to rising concerns over the depletion of fossil fuels and greenhouse gas emissions. Demand for portable electronic and wearable devices is increasing, and electronic devices are becoming smaller. Energy harvesting is a technology for overcoming limitations such as battery size and usage time. In this paper, the V-I characteristic curve and internal resistance of thermal electric devices were analyzed, and MPPT control methods were compared. The Perturbation and Observation (P&O) control method is economically inefficient because two sensors are required to measure the voltage and current of a Thermoelectric Generator(TEG). Therefore, this paper proposes a new MPPT control method that tracks MPP using only one sensor for the regulation of the output voltage. The proposed MPPT control method uses the relationship between the output voltage of the load and the duty ratio. Control is done by periodically sampling the output voltage of the DC-DC converter to increase or decrease the duty ratio to find the optimal duty ratio and maintain the MPP. A DC-DC converter was designed using a cascaded boost-buck converter, which has a two-switch topology. The proposed MPPT control method was verified by simulations using PSIM, and the results show that a voltage, current, and power of V=4.2 V, I=2.5 A, and P=10.5 W were obtained at the MPP from the V-I characteristic curve of the TEG.

A Study on the SAR Measurement System Validation at 150 MHz Band (150 MHz 대역에서의 SAR 측정시스템의 유효성 연구)

  • Choi, Donggeun;Kim, Kihwea;Choi, Jaehoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.10
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    • pp.1008-1016
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    • 2013
  • SAR measurement which was applied only to the mobile phone has been expanded in the Korean radio regulation law to the portable wireless communication equipments within 20 cm from the human body since Jan. 2012. The two-way radio operating at 150 MHz frequency band was newly included following the revised radio regulation in the target equipment of measurement. SAR measurement system at 150 MHz satisfying this regulation is necessary accordingly for SAR conformity assessment. The international SAR measurement standard(IEC 62209-2) includes the evaluation method on frequencies above 300 MHz, and the commercial SAR measurement system can measure SAR above 300 MHz only. The size of the reference dipole antenna(760 mm, return loss: -27.57 dB) and flat phantom ($1,300 mm(L){\times}900 mm(W){\times}200 mm(H)$), targeted SAR values for numerical analysis(1 g: 1.08 W/kg, 10 g: 0.77 W/kg) for SAR validation evaluation at 150 MHz frequency are proposed in this paper. The suggested dipole antenna and flat phantom are assembled and used to verify the conformity assessment of commercial SAR measurement system. The measured SAR values of 1 g and 10 g were obtained respectively to be 1.13 W/kg, 0.81 W/kg, and they satisfied the effective range(within ${\pm}10$ %) of IEC international standard. The standards based on this study are expected to be used for the domestic SAR measurement standard and IEC(International Electrotechnical Commission) international standard.

The Scheme for Delegation of Temporary Right to Watching Pay-TV in N-Screen Service (유료 콘텐츠의 N-스크린 서비스를 위한 일시적 시청권한 위임 기법)

  • Kim, Jung-Hoon;Lee, Hoon-Jung;Kim, Sang-Jin;Oh, Hee-Kuck
    • The KIPS Transactions:PartC
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    • v.18C no.3
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    • pp.135-142
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    • 2011
  • Recently, the strategy for N-screen service is in the spotlight along with the consumer's need to use contents regardless of time and place due to the rapid development of communication technology, which is meshing with the desire of service providers seeking a new business model. N-screen, as a screen-extension-concept service which enables consumers to continuously share and use contents in various equipments such as TV, computer and portable terminals, is an advanced type of 3-screen service strategy initially proposed by AT&T, an American telecommunication company. In the N-screen service for pay-contents, in order to support continuous screen changes to and from various equipments, temporary watching right should be given to the equipment intended for screen change. However, it is impossible to give the temporary watching right in the present broadcasting environment, adopting an access-control system. In this paper, the access-control technology being used for pay-contents in the present broadcasting environment and the reason for not being able to give temporary watching right, will be examined. After the examination, the solution for delegation of watching right by using an additional key on the basis of currently used access-control technology, will be proposed.

QR-Code Based Mutual Authentication System for Web Service (웹 서비스를 위한 QR 코드 기반 상호 인증 시스템)

  • Park, Ji-Ye;Kim, Jung-In;Shin, Min-Su;Kang, Namhi
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39B no.4
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    • pp.207-215
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    • 2014
  • Password based authentication systems are most widely used for user convenience in web services. However such authentication systems are known to be vulnerable to various attacks such as password guessing attack, dictionary attack and key logging attack. Besides, many of the web systems just provide user authentication in a one-way fashion such that web clients cannot verify the authenticity of the web server to which they set access and give passwords. Therefore, it is too difficult to protect against DNS spoofing, phishing and pharming attacks. To cope with the security threats, web system adopts several enhanced schemes utilizing one time password (OTP) or long and strong passwords including special characters. However there are still practical issues. Users are required to buy OTP devices and strong passwords are less convenient to use. Above all, one-way authentication schemes generate several vulnerabilities. To solve the problems, we propose a multi-channel, multi-factor authentication scheme by utilizing QR-Code. The proposed scheme supports both user and server authentications mutually, thereby protecting against attacks such as phishing and pharming attacks. Also, the proposed scheme makes use of a portable smart device as a OTP generator so that the system is convenient and secure against traditional password attacks.

Design of a High-Resolution Integrating Sigma-Delta ADC for Battery Capacity Measurement (배터리 용량측정을 위한 고해상도 Integrating Sigma-Delta ADC 설계)

  • Park, Chul-Kyu;Jang, Ki-Chang;Woo, Sun-Sik;Choi, Joong-Ho
    • Journal of IKEEE
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    • v.16 no.1
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    • pp.28-33
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    • 2012
  • Recently, with mobile devices increasing, as a variety of multimedia functions are needed, battery life is decreased. Accordingly the methods for extending the battery life has been proposed. In order to implement these methods, we have to know exactly the status of the battery, so we need a high resolution analog to digital converter(ADC). In case of the existing integrating sigma-delta ADC, it have not convert reset-time conversion cycle to function of resolution. Because of this reason, all digital values corresponding to the all number of bits will not be able to be expressed. To compensated this drawback, this paper propose that all digital values corresponding to the number of bits can be expressed without having to convert reset-time additional conversion cycle to function of resolution by using a up-down counter. The proposed circuit achieves improved SNDR compared to conventional converters simulation result. Also, this was designed for low power suitable for battery management systems and fabricated in 0.35um process.

광학 분석 시스템용 수.발광 소자 집적 모듈 개발

  • Song, Hong-Ju;Lee, Jun-Ho;Park, Jong-Hwan;Han, Cheol-Gu;Park, Jeong-Ho
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.311-312
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    • 2012
  • 본 발표에서는 광학적 분석 시스템에 적용 가능한 발광소자(광원)과 수광소자(광센서)를 집적화시키는 모듈(수 발광 집적모듈) 기술을 제시하고자 한다. 이러한 수-발광 집적모듈은 다양한 응용 분야에 적용 될 수 있다. 예를 들어, 광신호 감지를 위한 광통신용 송-수신 모듈(optical communication), 의료/진단 분야에서 단백질/DNA/박테리아 등의 검출 및 분석에 관한 바이오 센서(bio-sensor), 그리고 대기(가스)/수질 모니터링에 관한 환경센서 등 매우 광범위한 분야에 해당되는 요소 기술이라 할 수 있다. 특히, 이들 분야들 중 바이오 물질을 분석하고 검출하는 광학적 바이오 센서 기술은 높은 경제적 가치와 산업적 성장 잠재력으로 인해 오랫동안 활발한 연구가 진행되어 오고 있다. 이러한 광학적 바이오 센서에서 가장 범용적인 방법 중 하나가 항온-항체 면역반응을 기반으로 하는 형광 검출(fluorescence detection) 기법이다. 이러한 시스템은 전체적으로 광원, 광학계, 그리고 센서로 구성되는데 기존에 일반적으로 사용되고 있는 형광 현미경의 경우는 민감도가 우수하다는 장점은 있으나 상당히 고가이고 부피가 크며 복잡한 광학구성으로 이루어져 있다는 한계점을 가지고 있다. 이러한 맥락에서 고민감도를 확보하면서 휴대성, 고속처리, 저가 등의 특성을 가진 시스템에 대한 요구가 갈수록 증가하고 있다. 이를 해결하기 위한 핵심기술 중의 하나가 수-발광 부분을 집적화 시키는 기술이라 할 수 있다. 본 연구에서는 바이오 센서 기술의 하나로서 형광을 측정하여 혈액내의 진단 지표인자를 검출할 수 있는 휴대용 혈액진단기기에 적용되는 소형 수 발광 집적 모듈을 개발하였다. 혈액내의 검출 성분의 양에 따라 형광의 세기가 변화하게 됨으로써 정량적인 검출이 가능한 원리이다. 모듈의 구조는 크게 광원(발광소자), 광학계, 그리고 광센서(수광소자) 세 영역으로 나누어 진다. 광원은 635 nm 적색 레이저다이오드로서 형광체(Alexa Fluor 647/발광파장: 668 nm)를 여기 시키는 기능을 하며 장착된 볼렌즈 의해 샘플의 형광체 영역으로 집광된다. 광학계는 크게 시준렌즈(collimating lens)와 광학필터로 구성됨으로써 샘플로부터 발생되는 광을 적절하게 수광소자로 전달하는 기능을 하게 된다. 여기서 광학필터의 경우는 기본적으로 Distributed Bragg's Reflector(DBR) 구조로써 실리콘(Si) 포토다이오드 상부에 모노리식(monolithic)하게 형성되며 검출 샘플로부터 진행되는 레이저 광(잡음의 주원인)은 차단하고 형광(광신호)만 통과 시키는 기능을 하게 된다. 따라서 신호 대 잡음비(S/N ratio)를 향상시키기 위해서는 정밀한 광 필터링 기능이 요구됨으로써 박막의 세밀한 공정 조건과 구조적-광학적 특성 분석이 수행되었다. 마지막으로 포토다이오드 소자는 일반적인 구조 이외에 중앙에 원형 구멍이 형성된 특별한 구조가 적용된다. 이것은 포토다이오드 구조에 변화를 줌으로써 모듈 구조를 효율적으로 응용할 수 있다는 의미를 갖는다. 또한 포토다이오드의 전기적-광학적 측정 분석을 통해 잡음 및 감도 특성이 세부적으로 조사되며 형광신호를 효과적으로 측정할 수 있음을 확인하였다. 최종적으로 제작된 모듈은 약 $1{\times}1{\times}1cm^3$ 내외 정도의 크기를 갖는다. 요약하자면 본 발표에서는 광학적 바이오센서에 적용할 수 있는 소형 수-발광 소자 집적모듈을 소개한다. 전체 모듈 설계는 최소한의 부피를 가짐과 동시에 측정의 정밀성을 향상시키는데 초점을 맞추어 진행하였다. 세부요소인 광학필터와 포트다이오드의 경우 잡음 및 민감도에 미치는 중요성 때문에 세밀한 공정 및 특성분석이 수행되었다. 결론적으로 독자적인 설계 및 공정을 통해 휴대성 및 정밀성 등의 목적에 부합한 경쟁력 있는 수-발광 소자 집적모듈 제작 기술을 확보하였다.

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