• Title/Summary/Keyword: Dimensional Design

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Novel Radix-26 DF IFFT Processor with Low Computational Complexity (연산복잡도가 적은 radix-26 FFT 프로세서)

  • Cho, Kyung-Ju
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.13 no.1
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    • pp.35-41
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    • 2020
  • Fast Fourier transform (FFT) processors have been widely used in various application such as communications, image, and biomedical signal processing. Especially, high-performance and low-power FFT processing is indispensable in OFDM-based communication systems. This paper presents a novel radix-26 FFT algorithm with low computational complexity and high hardware efficiency. Applying a 7-dimensional index mapping, the twiddle factor is decomposed and then radix-26 FFT algorithm is derived. The proposed algorithm has a simple twiddle factor sequence and a small number of complex multiplications, which can reduce the memory size for storing the twiddle factor. When the coefficient of twiddle factor is small, complex constant multipliers can be used efficiently instead of complex multipliers. Complex constant multipliers can be designed more efficiently using canonic signed digit (CSD) and common subexpression elimination (CSE) algorithm. An efficient complex constant multiplier design method for the twiddle factor multiplication used in the proposed radix-26 algorithm is proposed applying CSD and CSE algorithm. To evaluate performance of the previous and the proposed methods, 256-point single-path delay feedback (SDF) FFT is designed and synthesized into FPGA. The proposed algorithm uses about 10% less hardware than the previous algorithm.

Design of RFID Authentication Protocol Using 2D Tent-map (2차원 Tent-map을 이용한 RFID 인증 프로토콜 설계)

  • Yim, Geo-su
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.13 no.5
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    • pp.425-431
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    • 2020
  • Recent advancements in industries and technologies have resulted in an increase in the volume of transportation, management, and distribution of logistics. Radio-frequency identification (RFID) technologies have been developed to efficiently manage such a large amount of logistics information. The use of RFID for management is being applied not only to the logistics industry, but also to the power transmission and energy management field. However, due to the limitation of program development capacity, the RFID device is limited in development, and this limitation is vulnerable to security because the existing strong encryption method cannot be used. For this reason, we designed a chaotic system for security with simple operations that are easy to apply to such a restricted environment of RFID. The designed system is a two-dimensional tent map chaotic system. In order to solve the problem of a biased distribution of signals according to the parameters of the chaotic dynamical system, the system has a cryptographic parameter(𝜇1), a distribution parameter(𝜇2), and a parameter(𝜃), which is the constant point, ID value, that can be used as a key value. The designed RFID authentication system is similar to random numbers, and it has the characteristics of chaotic signals that can be reproduced with initial values. It can also solve the problem of a biased distribution of parameters, so it is deemed to be more effective than the existing encryption method using the chaotic system.

Image Compression Using DCT Map FSVQ and Single - side Distribution Huffman Tree (DCT 맵 FSVQ와 단방향 분포 허프만 트리를 이용한 영상 압축)

  • Cho, Seong-Hwan
    • The Transactions of the Korea Information Processing Society
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    • v.4 no.10
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    • pp.2615-2628
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    • 1997
  • In this paper, a new codebook design algorithm is proposed. It uses a DCT map based on two-dimensional discrete cosine of transform (2D DCT) and finite state vector quantizer (FSVQ) when the vector quantizer is designed for image transmission. We make the map by dividing input image according to edge quantity, then by the map, the significant features of training image are extracted by using the 2D DCT. A master codebook of FSVQ is generated by partitioning the training set using binary tree based on tree-structure. The state codebook is constructed from the master codebook, and then the index of input image is searched at not master codebook but state codebook. And, because the coding of index is important part for high speed digital transmission, it converts fixed length codes to variable length codes in terms of entropy coding rule. The huffman coding assigns transmission codes to codes of codebook. This paper proposes single-side growing huffman tree to speed up huffman code generation process of huffman tree. Compared with the pairwise nearest neighbor (PNN) and classified VQ (CVQ) algorithm, about Einstein and Bridge image, the new algorithm shows better picture quality with 2.04 dB and 2.48 dB differences as to PNN, 1.75 dB and 0.99 dB differences as to CVQ respectively.

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The Response Prediction of Flexible Pavements Considering Nonlinear Pavement Foundation Behavior (비선형 포장 하부 거동을 고려한 연성 포장의 해석)

  • Kim, Min-Kwan
    • International Journal of Highway Engineering
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    • v.11 no.1
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    • pp.165-175
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    • 2009
  • With the current move towards adopting mechanistic-empirical concepts in the design of pavement structures, state-of-the-art mechanistic analysis methodologies are needed to determine accurate pavement responses, such as stress, strain, and deformation. Previous laboratory studies of pavement foundation geomaterials, i.e., unbound granular materials used in base/subbase layers and fine-grained soils of a prepared subgrade, have shown that the resilient responses followed by nonlinear, stress-dependent behavior under repeated wheel loading. This nonlinear behavior is commonly characterized by stress-dependent resilient modulus material models that need to be incorporated into finite element (FE) based mechanistic pavement analysis methods to predict more realistically predict pavement responses for a mechanistic pavement analysis. Developed user material subroutine using aforementioned resilient model with nonlinear solution technique and convergence scheme with proven performance were successfully employed in general-purpose FE program, ABAQUS. This numerical analysis was investigated in predicted critical responses and domain selection with specific mesh generation was implemented to evaluate better prediction of pavement responses. Results obtained from both axisymmetric and three-dimensional (3D) nonlinear FE analyses were compared and remarkable findings were described for nonlinear FE analysis. The UMAT subroutine performance was also validated with the instrumented full scale pavement test section study results from the Federal Aviation Administration's National Airport Pavement Test Facility (FAA's NAPTF).

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Color Change and Consumer Preferences towards Color of Heat-Treated Korean White Pine and Royal Paulownia Woods

  • Hidayat, Wahyu;Qi, Yue;Jang, Jae Hyuk;Park, Byung Ho;Banuwa, Irwan Sukri;Febrianto, Fauzi;Kim, Nam Hun
    • Journal of the Korean Wood Science and Technology
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    • v.45 no.2
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    • pp.213-222
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    • 2017
  • Heat treatment of wood is an attractive alternative environmentally-friendly treatment to add value of less valuable woods by improving color, dimensional stability, and natural durability. To improve the color properties of Korean white pine (Pinus koraiensis) and royal paulownia (Pauwlonia tomentosa), we treated the woods at $160^{\circ}C$, $180^{\circ}C$, $200^{\circ}C$, and $220^{\circ}C$ for 2 hours. Color change after heat treatment was evaluated using the CIE-Lab color system and survey was conducted to determine the consumer preferences towards color of heat-treated wood. Lightness ($L^*$) decreased with increasing temperature and the higher degree of change was obtained in royal paulownia. The red/green chromaticity ($a^*$) in both wood decreased after heat treatment at $160^{\circ}C$, and constantly increased after heat treatment at $180^{\circ}C$ to $220^{\circ}C$. Yellow/blue chromaticity ($b^*$) in Korean white pine tended to increase after heat treatment at $160^{\circ}C$, then decreased gradually afterwards. In royal paulownia, $b^*$ values linearly increased with increasing temperature. Overall color change (${\Delta}E^*$) increased with increasing temperature with higher degree obtained in royal paulownia. Samples with the clamps in both wood species showed lower degree of the change in $L^*$, $a^*$, b and ${\Delta}E^*$. The results of the consumer preferences test showed that the darker colors of heat-treated woods were more preferred by consumers compared to the lighter colors of untreated woods. Consequently, heat treatment could enhance the color properties of Korean white pine and royal paulownia woods for value added products.

Reconstruction with Radial Forearm Free Flap after Ablative Surgery for Oral Cavity and Oropharyngeal Cancers (구강암과 구인두암의 절제술 후 전완유리피판술을 이용한 재건술)

  • Cho Kwang-Jae;Chun Byung-Jun;Sun Dong-Il;Cho Seung-Ho;Kim Mn-Sik
    • Korean Journal of Head & Neck Oncology
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    • v.19 no.1
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    • pp.41-46
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    • 2003
  • Background and Objectives: Surgical ablation of tumors in the oral cavity and the oropharynx results in a three dimensional defect because of the needs to resect the adjacent area for the surgical margin. Although a variety of techniques are available, radial forearm free flap has been known as an effective method for this defect, which offers a thin, pliable, and relatively hairless skin and a long vascular pedicle. We report the clinical results of our 54 consecutive radial forearm free flaps used for oral cavity and oropharynx cancers. Materials and Methods: We reviewed the medical records of patients who were offered intraoral reconstruction with a radial forearm free flap after ablative surgery for oral cavity and oropharyngeal cancers from August 1994 to February 2003 and analyzed surgical methods, flap survival rate, complication, and functional results. Among these, 20 cases were examined with modified barium swallow to evaluate postoperative swallowing function and other 8 cases with articulation and resonance test for speech. We examined recovery of sensation with two-point discrimination test in 15 cases who were offered sensate flaps. Results: The primary sites were as follows : mobile tongue (18), tonsil (17), floor of mouth (4), base of tongue (2), soft palate (2), retromolar trigone (3), buccal mucosa (1), oro-hypopharynx (6), and lower lip (1). The paddles of flaps were tailored in multilobed designs from oval shape to tetralobed design and in variable size according to the defects after ablation. This procedures resulted in satisfactory flap success rate (96.3%) and showed good swallowing function and social speech. Eight of 15 cases (53.3%) who had offered sensate flap showed recovery of sensation between 1 and 6 postoperative months (average 2.6 month). Conclusion: The reconstruction with radial forearm free flap might be an excellent method for the maximal functional results after ablative surgery of oral cavity and oropharyngeal cancers that results in multidimensional defect.

Development of a Software to Evaluate the CPES(Cable Penetration Fire Stop) System in Nuclear Power Plane I (원자력발전소 케이블관통부 충전시스템 평가용 소프트웨어 개발 I)

  • 윤종필;권성필;조재규;윤인섭
    • Fire Science and Engineering
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    • v.18 no.1
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    • pp.24-30
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    • 2004
  • In this work the dynamic heat transfer occurring in a cable penetration fire stop system built in the firewall of nuclear power plants is three-dimensionally investigated to develop a test-simulator that can be used to verify effectiveness of the sealants. Here was carried out an experiment to observe the heat transfer in the cable penetration fire stop system made of DOW CORNING products. The dynamic heat transfer occurring in the fire stop system is formulated in a parabolic partial differential equation subjected to a set of initial and boundary conditions. And it was modeled, simulated, and analyzed. The simulation results were illustrated in three-dimensional graphics and were compared with experimental data. Through the simulations, it was shown clearly that the temperature distribution was influenced very much by the number, position, and temperature of the cable streams. It also was found that the dynamic heat transfer through the cable streams was one of the most dominant factors, and the feature of heat conduction could be understood as an unsteady-state process. It is certain that these numerical results are useful for making a performance-based design for the cable penetration fire stop system.

Verification Method for Quantity Takeoff Results of Concrete Works using Design Drawing Information (도면정보 기반 건축공사 콘크리트 물량산출 성과물 검증방안 개발)

  • Lim, Haejin;Choi, Chang-Hoon;Han, Choong-Hee;Lee, Junbok
    • Korean Journal of Construction Engineering and Management
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    • v.21 no.5
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    • pp.20-28
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    • 2020
  • In construction project, an error in quantity information immediately leads to an error in the quotation, highly reliable quantity calculation is required for successful performance of a project. But there is a difficulty in the current situation for the person in charge to review all calculation sheets for quantity review as the quotation work has to be performed in a short period of time. Accordingly, it is thought that a review plan is required to secure reliability on calculated results and the review plan should be able to be carried out within insufficient quotation periods. In the present paper, it is intended to present a plan that enables quantity to be reviewed with the minimum number of persons within the shortest period of time through an algorithm of calculating a verification quantity. The suggested algorithm allows the result of quantity calculation work carried out earlier based on 2-dimensional drawing to be compared, not with an accurate quantity, but within an error range.

Uncoupled Solution Approach for treating Fluid-Structure Interaction due to the Near-field Underwater Explosion (근거리 수중폭발에 따른 유체-구조 상호작용 취급을 위한 비연성 해석방법)

  • Park, Jin-Won
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.10
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    • pp.125-132
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    • 2019
  • Because the water exposed to shock waves caused by an underwater explosion cannot withstand the appreciable tension induced by the change in both pressure and velocity, the surrounding water is cavitated. This cavitating water changes the transferring circumstance of the shock loading. Three phenomena contribute to hull-plate damage; initial shock loading and its interaction with the hull plate, local cavitation, and local cavitation closure then shock reloading. Because the main concern of this paper is local cavitation due to a near-field underwater explosion, the water surface and the waves reflected from the sea bottom were not considered. A set of governing equations for the structure and the fluid were derived. A simple one-dimensional infinite plate problem was considered to verify this uncoupled solution approach compared with the analytic solution, which is well known in this area of interest. The uncoupled solution approach herein would be useful for obtaining a relatively high level of accuracy despite its simplicity and high computational efficiency compared to the conventional coupled method. This paper will help improve the understanding of fluid-structure interaction phenomena and provide a schematic explanation of the practical problem.

ROUTE/DASH-SRD based Point Cloud Content Region Division Transfer and Density Scalability Supporting Method (포인트 클라우드 콘텐츠의 밀도 스케일러빌리티를 지원하는 ROUTE/DASH-SRD 기반 영역 분할 전송 방법)

  • Kim, Doohwan;Park, Seonghwan;Kim, Kyuheon
    • Journal of Broadcast Engineering
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    • v.24 no.5
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    • pp.849-858
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    • 2019
  • Recent developments in computer graphics technology and image processing technology have increased interest in point cloud technology for inputting real space and object information as three-dimensional data. In particular, point cloud technology can accurately provide spatial information, and has attracted a great deal of interest in the field of autonomous vehicles and AR (Augmented Reality)/VR (Virtual Reality). However, in order to provide users with 3D point cloud contents that require more data than conventional 2D images, various technology developments are required. In order to solve these problems, an international standardization organization, MPEG(Moving Picture Experts Group), is in the process of discussing efficient compression and transmission schemes. In this paper, we provide a region division transfer method of 3D point cloud content through extension of existing MPEG-DASH (Dynamic Adaptive Streaming over HTTP)-SRD (Spatial Relationship Description) technology, quality parameters are further defined in the signaling message so that the quality parameters can be selectively determined according to the user's request. We also design a verification platform for ROUTE (Real Time Object Delivery Over Unidirectional Transport)/DASH based heterogeneous network environment and use the results to validate the proposed technology.