• Title/Summary/Keyword: 경량성

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Digital Data Communication System for Mobile Network System Using CC1020 Chip (CC1020 Chip을 사용한 모바일 네트워크를 위한 디지털 데이터 통신 시스템)

  • Lim, Hyun-Jin;So, Heung-Kuk
    • Journal of the Institute of Convergence Signal Processing
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    • v.8 no.1
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    • pp.58-62
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    • 2007
  • Digital communication is important for reliability and mobilization of the multi-channel communication systems. Transmitting and receiving data for the mobilization should be possible in anywhere and in anytime. And this system must be designed light weight small size and low power. One are essential technology for implementing the mobile wireless communication system on the age of ubiquotos. Requirements in constructing such communication field are followings. At first data transmitting and receiving should be carried out by a simple command. Second, the device should be designed as hand-hold type and low power consumption. Third, data communication should be reliable. As one of examples, car to car system which is popular in the market is introduced here, All traffic information in highway is transmitted from one car to another by using this system which can prevent possible traffic accident. This paper shows the design of a digital data communication system with CC1020 chip. This CC1020 makes easy frequency selection and easy switch from the transmit mode to the receive mode by simple setting of a memory register in the chip. The transmit power of this system is designed 10dBm and its communication range is about 100m. The power supplied this system is 3V considered as low power. The sleep mode can be easily entered during transmit mode or receive mode. We shows the program algorithm of CC1020 and interface circuit between MCU and CC1020. We shows the Photo of the CC1020 Module and Atmega128 Module.. We analysed the receiver rate with this system.

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A Study of Mock Objects Generator for Applying XPwith Special Attention to C (C환경에서의 XP적용을 위한 모크객체생성기에 관한 연구)

  • Jung Young Mok;Park Jae Won;Lee Nam Yong
    • Journal of the Korea Society of Computer and Information
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    • v.10 no.1 s.33
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    • pp.15-26
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    • 2005
  • As one of the lightweight software development methodology, the XP (Extreme Programming) is the practical means to improve the productivity and qualify of software through the pursuit of 4 values - communication, simplicity, feedback, and courage. It appears, however, the TDD (Test Driven Development). one of the practices of in. has a problem. which is the unavailability of the test driven development in case of the prolonged period of testing or the failure of securing the independency of the test cases. This results in the emphasis on the importance of the Mock Objects recently. The Mock Objects, the one imitating the faulty real code, has the fundamentals of simplicity allowing even manual script but. due to the inefficiency of manual script of the Mock Objects in a real life, it is implemented the Mock Objects Generator such as Mockotjects, EasyMock in Java. It Is found difficult, however to apply the Mock Objects in C language due to its object -oriented Premise as well as the absence of mock objects generators for C language. Therefore, in this Paper it is presented the CMock, a Mock Objects generator fer C language which allows the easy creation of the Mock Objects, and the study is performed to verify the efficiency accordingly.

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Sound Insulation Properties of Polymer Soundproof Panels (폴리머 계열 방음패널의 차음특성 비교 분석)

  • Lee, Woo-Mi;Lee, Ju Haeng;Son, Jin-Hee;Kim, Il-Ho;Park, Jae-Roh;Kim, Kwang Soo
    • Journal of Korean Society of Environmental Engineers
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    • v.35 no.8
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    • pp.592-597
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    • 2013
  • It is widely known that the sound insulation of soundproof panel is highly correlated to two factors, surface density of material and the frequency of noise. Accordingly, the character of traffic noise released in actual situation is important requisite for determining thickness to determine surface density and material of soundproof panel. This present study selected polymer panel with advantage of light weight and workability and evaluates according to frequency of traffic noise. Polypropylene (PP) and high-density polyethylene (HDPE) were selected as subjects based on economic valuation and efficiency. The sound transmission loss of selected polymer panels were compared with the currently used panels such as polycarbonate (PC) and polymethyl methacrylate (PMMA) depending on thickness and materials. As a result, PC showed the highest sound transmission loss followed by PMMA, HDPE, and PP in range of mass law. In terms of acoustic performance on thickness, the transmission loss increased with thickness of soundproof panel meanwhile coincidence dip was observed in lower frequency where had reduced transmission loss. Therefore, it is suggested that after determining target frequency, the kind of materials and thickness of soundproof panel need to be designed so that traffic noise can be more efficiently reduced.

An analysis of horizontal deformation of a pile in soil using a continuum soil model for the prediction of the natural frequency of offshore wind turbines (해상풍력터빈의 고유진동수 예측을 위한 지반에 인입된 파일의 연속체 지반 모델 기반 수평 거동 해석)

  • Ryue, Jungsoo;Baik, Kyungmin;Lee, Jong-Hwa
    • The Journal of the Acoustical Society of Korea
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    • v.35 no.6
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    • pp.480-490
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    • 2016
  • As wind turbines become larger and lighter, they are likely to respond sensitively by dynamic loads applied on them. Since the responses at resonances are particularly interested, it is required to be able to predict natural frequencies of wind turbines reliably at early design stage. To achieve this, the foundation-soil analysis is needed to be carried out and a finite element approach is adopted in general. However, the finite element approach would not be appropriate in early design stage because it demands heavy efforts in pile-soil modelling and computing facilities. On the contrary, theoretical approaches adopting linear approximations for soils are relatively simple and easy to handle. Therefore, they would be a useful tool in predicting a pile-soil interaction, particularly in early design stage. In this study an analysis for a pile inserted in soil is performed. The pile and soil are modelled as a beam and continuum medium, respectively, within an elastic range. In this analysis, influence factors at the pile head for lateral loads are predicted by means of this continuum approach for various length-diameter ratios of the pile. The influence factors predicted are validated with those reported in literature, proposed from a finite element analysis.

Electrical Output and Reliability of Photovoltaic Module Using Ethylene Tetrafluoroethylene Film (ETFE 필름을 적용한 태양광 모듈의 전기적 출력 및 신뢰성에 관한 연구)

  • Shin, Woogyun;Lim, Jongrok;Ko, Sukwhan;Kang, Gihwan;Ju, Youngchul;Hwang, Heymi
    • Journal of the Korean Solar Energy Society
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    • v.40 no.4
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    • pp.13-22
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    • 2020
  • As the supply of photovoltaic (PV) increases worldwide, the cumulative installations in 2018 were 7.9 and 560 GW in Korea and the world, respectively. Typically, when the ground on commercial PV modules is installed, the area is limited; hence, new designs of PV modules are required to install additional PVs. Among the new design of PV modules, lightweight PV modules can be utilized in PV systems, such as buildings, farmlands, and floating PV. Concerning the investigation of lightweight PV modules, several studies on materials for replacing low-iron tempered glass, which comprises approximately 65% of the PV module weight, have been conducted. However, materials that are used as substitutes for glass should possess similar lightweight properties and reliability as glass. In this study, experimental tests were performed to evaluate the applicability of ethylene tetrafluoroethylene (ETFE) film with excellent resistance to water and aging as a front material of PV modules. The transmittance and ultraviolet properties of the ETFE film were determined and compared with those of glass. A 1-cell module and laboratory-scale 24-cell module were manufactured using the ETFE film and glass, and the electrical output was measured and analyzed. Furthermore, damp heat and thermal cycle tests were conducted to evaluate the reliability of the ETFE film module. Based on the experimental results, the electrical output and reliability of the ETFE film module were similar to those of the glass module, and the ETFE film could be used as the front material of PV modules.

A Study on Low-Cost RFID System Mutual Authentication Scheme using Key Division (키 분할을 이용한 Low-Cost RFID 시스템 상호 인증 방안에 관한 연구)

  • Kang, Soo-Young;Lee, Im-Yeong
    • The KIPS Transactions:PartC
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    • v.14C no.5
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    • pp.431-438
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    • 2007
  • RFID system is core technology that construct ubiquitous environment for replacement of barcode technology. Use ratio of RFID system rapidly increase because the technology has many good points such as identification speed, storage space, convenience etc. But low-cost tag operates easily by query of reader, so the system happened user privacy violent problem by tag information exposure. The system studied many ways for security application, but operation capability of low-cost tag is about $5K{\sim}10K$ gates, but only $250{\sim}3K$ gates allocated security part. So it is difficult to apply security to the system. Therefore, this scheme uses dividing 64 bits and reduces arithmetic, so proposed scheme provide mutual authentication that can apply to low-cost RFID system. Existing methods divide by 4 and used 96 bits. However, that reduces 32 bits length for lightweight and reduced from communication number of times of 7 times to 5 times. Also, because offer security by random number than existing scheme that generate two random numbers, that is more efficient. However, uses hash function for integrity that was not offered by XOR arithmetic and added extension of proposed scheme. Extended scheme is not offered efficiency than methods that use XOR arithmetic, but identification distance is mode that is proposed secure so that can use in for RFID system.

A PDWZ Encoder Using Code Conversion and Bit Interleaver (코드변환과 비트 인터리버를 이용한 화소영역 Wyner-Ziv 부호화 기법)

  • Kim, Jin-Soo;Kim, Jae-Gon;Seo, Kwang-Deok
    • Journal of Broadcast Engineering
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    • v.15 no.1
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    • pp.52-62
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    • 2010
  • Recently, DVC (Distributed Video Coding) is attracting a lot of research works since this enables us to implement a light-weight video encoder by distributing the high complex tasks such as motion estimation into the decoder side. In order to improve the coding efficiency of the DVC, the existing works have been focused on the efficient generation of side information (SI) or the virtual channel modeling which can describe the statistical channel noise well. But, in order to improve the overall performance, this paper proposes a new scheme that can be implemented with simple bit operations without introducing complex operation. That is, the performance of the proposed scheme is enhanced by using the fact that the Wyner-Ziv (WZ) frame and side information are highly correlated, and by reducing the effect of virtual channel noise which tends to be clustered in some regions. For this aim, this paper proposes an efficient pixel-domain WZ (PDWZ) CODEC which effectively exploits the statistical redundancy by using the code conversion and Gray code, and then reduces the channel noise by using the bit interleaver. Through computer simulations, it is shown that the proposed scheme can improve the performance up to 0.5 dB in objective visual quality.

필름 스피커 적용을 위한 PZT/polymer 복합체의 후막 제조 및 압전 특성 평가

  • Son, Yong-Ho;Eo, Sun-Cheol;Kim, Seong-Jin;Gwon, Seong-Yeol;Gwon, Sun-Yong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.346-346
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    • 2007
  • 압전세라믹 재료는 현재 압전 변압기, actuator, transducer, sensor, speaker 등에 광범위하게 이용이 되고 있다. 이 중에서 압전세라믹 소결체를 이용한 스피커의 제조는 가공이 까다롭고, 대형의 크기로 제작 시 소자가 깨지는 등의 많은 제약을 받고 있으며, 저음 특성이 떨어져 응용 범위가 한정되어 있다. 따라서 최근에는 이러한 단점을 극복하기 위하여 세라믹/고분자 복합체를 이용한 필름 스피커를 제작하고자 시도하고 있다. 이러한 세라믹/고분자 0-3형 압전 복합체를 이용할 경우, 제품의 경량화를 실현할 수 있고, 크기나 환경의 영향을 거의 받지 않으므로, 고기능성 스피커로의 응용에 적합할 것으로 보인다. 따라서 본 연구에서는 PZT계의 세라믹와 PVDF, PVDF-TrFE, Polyester, acrylic resin 등의 여러 고분자 물질과의 복합체를 제조하여 압전특성을 평가하였다. 본 실험은 먼저 $(Pb_{1-a-b}Ba_aCd_b)(Zr_xTi_{1-x})_{1-c-d}(Ni_{1/3}Nb_{2/3})_c(Zn_{1/3}Nb_{2/3})_dO_3$ (이하 PZT라 표기)의 최적화 조성을 선택하여, $1050^{\circ}C$에서 소결된 분말을 48시간 ball milling방법 로 약 $1{\mu}m$ 크기로 분쇄하였다. 고분자 물질들은 알맞은 용제들을 선택하여 녹였다. 그 다음 소결된 PZT분말과 고분자를 50:50, 60:40, 65:35, 70:30등의 무게 분율로 혼합하고, 분산제, 소포제 등을 첨가하여 3단 roll mill을 이용하여 충분히 분산시켜 페이스트 (Paste)를 제조하였다. 제조된 페이스트를 ITO가 코팅된 PET필름 위에 스크린 프린팅 법을 사용하여 인쇄하여 $120^{\circ}C$에서 5분간 건조하였다. 코팅된 복합체의 두께는 약 $80{\mu}m$ 정도로 측정되었다. Ag 페이스트를 이용한 상부 전극 형성에도 스크린 프린팅 법을 적용하였다. 이를 $120^{\circ}C$에서 4 kV/mm의 DC 전계로 분극 공정을 수행한 후 전기적 특성을 평가하였다. 유전특성을 조사하기 위해서 LCR meter (EDC-1620)를 사용하였고, 시편의 결정구조는 XRD (Rigaku; D/MAX-2500H)을 통해 분석하였으며, 전자현미경(SEM)을 이용하여 미세구조를 분석하였다. 압전 전하상수$(d_{33})$ 값은 APC 8000 모델을 이용하여 측정하였다. PZT의 혼합비가 증가할수록 비유전율 및 압전 전하 상수 등의 전기적 특성이 증가되었다. 또 여러 고분자 물질 중에서 PVDF-TrFE 수지가 가장 우수한 특성을 보였다. 이는 PVDF-TrFE 수지가 압전성을 나타내기 때문인 것으로 판단되었다.

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Utilization of Finite Element Analysis in Design and Performance Evaluation of CFRP Bicycle Frames (유한요소해석을 이용한 CFRP 자전거 프레임의 설계 및 성능 평가)

  • Lee, Yong-Sung;Shin, Ki-Hoon;Cheong, Seong-Kyun;Choi, Ung-Jae;Kim, Young-Keun;Park, Kyung-Rea;Kim, Hong Seok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.1
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    • pp.121-127
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    • 2013
  • With the continuing demand for lightweight bicycles, carbon fiber composite materials have been widely used in manufacturing bicycle frames and components. Unlike general isotropic materials, the structural characteristics of composite materials are strongly influenced by the staking directions and sequences of composite laminates. Thus, to verify the design process of bicycles manufactured using composites, structural analysis is considered essential. In this study, a carbon-fiber-reinforced plastic (CFRP) bicycle frame was designed and its structural behavior was investigated using finite element analysis (FEA). By measuring the failure indices of the fiber and matrix under various stacking sequences and loading conditions, the effect of the stacking condition of composite laminates on the strength of the bicycle structure was examined. In addition, the structural safety of the bicycle frame can be enhanced by reinforcing weak regions prone to failure using additional composite laminates.

Evaluation and Modification of Tensile Properties of Carbon Fiber Reinforced Polymer(CFRP) as Brittle Material with Probability Distribution (확률분포를 이용한 취성재료 특성의 탄소섬유보강폴리머 인장물성평가 및 보정)

  • Kim, Yun-Gon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.23 no.3
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    • pp.17-24
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    • 2019
  • Carbon Fiber Reinforced Polymers(CFRP) has widely utilized as a material for rehabilitation because of its light-weight, deformability and workability. Because CFRP is brittle material whereas steel is ductile, it is inappropriate to apply conventional design approach for steel reinforcement. For ductile material, the behavior of combined elements is on average of that of unit element due to the stress redistribution between elements after yielding. Therefore, the mean value of the stress of combined elements is equal to that of unit element and the standard variation is smaller. Therefore, although the design value can increase, it is used as constant value because it is conservative and practical approach. However, for brittle material, the behavior of combined elements is governed by the weaker element because no stress redistribution is expected. Therefore, both the mean value and standard variation of the stress of combined elements decreases. For this reason, the design value would decrease as the number of element increases although it is eventually converged. In this paper, in brittle material, it is verified that the combination of unit element with normal distribution results in combined element with weibull distribution, so the modifying equation of mechanical properties is proposed with respect to the area load applied.