• Journal of Biosystems Engineering
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• 제24권2호
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• pp.159-166
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• 1999

A system to extract continuously the real 3-D geometric fearture information from 2-D image of an object, which is fed randomly via conveyor has been developed. Two sets of structured laser lightings were utilized. And the laser structured light projection image was acquired using the camera from the signal of the photo-sensor mounted on the conveyor. Camera coordinate calibration matrix was obtained, which transforms 2-D image coordinate information into 3-D world space coordinate using known 6 points. The maximum error after calibration showed 1.5 mm within the height range of 103mm. The correlation equation between the shift amount of the laser light and the height was generated. Height information estimated after correlation showed the maximum error of 0.4mm within the height range of 103mm. An interactive 3-D geometric feature extracting software was developed using Microsoft Visual C++ 4.0 under Windows system environment. Extracted 3-D geometric feature information was reconstructed into 3-D surface using MATLAB.

• 대한전자공학회논문지SP
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• 제46권1호
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• pp.49-55
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• 2009

본 논문에서는 임의의 직교 블록 변환 영역에서 직접 영상 크기를 변경하는 기법을 개발한다. 이를 위해, 임의 직교 변환영역에서 영상 크기 변환을 수행하는 모든 과정을 행렬 곱으로 표현하여, 해상도 변환을 수행하는 행렬을 유도한다. 해상도 변환 행렬은 영상 특성에 따라 직교 블록 변환에 알맞은 일반식으로 설계한다. 개발된 기법은 기존의 실수 DCT 영역 뿐만 아니라 H.264/AVC에 적용 가능한 $4{\times}4$ Modified DCT 및 Hadamard 변환과 같은 다양한 직교 변환 영역에 적용할 수 있고, 동영상 부호화 시 사용되는 대표적인 시퀀스 영상들의 해상도 변환에 적용 가능함을 실험을 통하여 검증하였다.

• Structural Engineering and Mechanics
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• 제43권5호
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• pp.561-582
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• 2012

Despite popularity of FEM in analysis of static and dynamic structural problems and the routine applicability of FE softwares, analytical methods based on simple mathematical relations is still largely sought by many researchers and practicing engineers around the world. Development of such analytical methods for analysis of free vibration of non-prismatic beams is also of primary concern. In this paper a new and simple method is proposed for determination of vibration frequencies of non-prismatic beams under variable axial forces. The governing differential equation is first obtained and, according to a harmonic vibration, is converted into a single variable equation in terms of location. Through repetitive integrations, integral equation for the weak form of governing equation is derived. The integration constants are determined using the boundary conditions applied to the problem. The mode shape functions are approximated by a power series. Substitution of the power series into the integral equation transforms it into a system of linear algebraic equations. Natural frequencies are determined using a non-trivial solution for system of equations. Presented method is formulated for beams having various end conditions and is extended for determination of the buckling load of non-prismatic beams. The efficiency and convergence rate of the current approach are investigated through comparison of the numerical results obtained to those obtained using available finite element software.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2184-2186
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• 2001

The research presented in this paper focuses on a method for the detection of High Impedance Fault(HIF). The method will use the fast wavelet transform and neural network system. HIF on the multi-grounded three-phase four-wires primary distribution power system cannot be detected effectively by existing over current sensing devices. These paper describes the application of fast wavelet transform to the various HIF data. These data were measured in actual 22.9kV distribution system. Wavelet transform analysis gives the frequency and time-scale information. The neural network system as a fault detector was trained to discriminate HIF from the normal status by a gradient descent method. The proposed method performed very well by proving the right state when it was applied staged fault data and normal load mimics HIF, such as arc-welder.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권1호
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• pp.1-9
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• 2004

In this paper, we proposed a hardware(H/W) structure which can compress and recontruct the input image in real time operation and implemented it into a FPGA platform using VHDL(VHSIC Hardware Description Language). All the image processing element to process both compression and reconstruction in a FPGA were considered each of them was mapped into a H/W with the efficient structure for FPGA. We used the DWT(discrete wavelet transform) which transforms the data from spatial domain to the frequency domain, because use considered the motion JPEG2000 as the application. The implemented H/W is separated to both the data path part and the control part. The data path part consisted of the image processing blocks and the data processing blocks. The image processing blocks consisted of the DWT Kernel for the filtering by DWT, Quantizer/Huffman Encoder, Inverse Adder/Buffer for adding the low frequency coefficient to the high frequency one in the inverse DWT operation, and Huffman Decoder. Also there existed the interface blocks for communicating with the external application environments and the timing blocks for buffering between the internal blocks. The global operations of the designed H/W are the image compression and the reconstruction, and it is operated by the unit or a field synchronized with the A/D converter. The implemented H/W used the 54％(12943) LAB(Logic Array Block) and 9％(28352) ESB(Embedded System Block) in the APEX20KC EP20K600CB652-7 FPGA chip of ALTERA, and stably operated in the 70MHz clock frequency. So we verified the real time operation. that is. processing 60 fields/sec(30 frames/sec).

• 정보처리학회논문지A
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• 제18A권2호
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• pp.39-44
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• 2011

본 논문은 통합 비디오 코덱에 적용할 수 있는 DCT와 양자화 회로에 대한 고성능 구조를 제안한다. 제안된 구조는 JPEG, MPEG-1/2/4, H.264, VC-1과 같은 동영상 압축 표준들에 사용되는 모든 변환과 양자화에 적용할 수 있다. 통합 DCT 회로 구조를 위해 8x8 DCT의 변환행렬을 재배치하는 순열행렬을 정의하였고 $4{\times}4$ DCT의 변환행렬과 통합하기 위해 $8{\times}8$ 변환행렬을 4개의 $4{\times}4$ 변환행렬로 나누었다. $8{\times}8$ DCT는 재배치와 분할된 변환행렬을 기반으로 $4{\times}4$ DCT 연산을 반복하여 수행된다. 구현된 회로는 사용자가 변환 계수를 입력하기 때문에 앞으로 등장할 어떤 종류의 DCT 변환에도 매우 쉽게 확장할 수 있다. DCT 회로의 곱셈기들은 회로 크기를 최소화하기 위해 양자화 회로에서 사용되는 곱셈기들과 공유하였다. 이때, 양자화 회로는 회로 구현에 필요한 자원과 처리 시간의 증가 없이 DCT 회로와 통합된다. 제안된 DCT와 양자화 회로는 RTL로 구현하였고 FPGA가 탑재된 보드에서 동작을 검증하였다.

• 한국자기공명학회논문지
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• 제9권1호
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• pp.1-20
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• 2005

Vanadium-incorporated aluminophophate molecular sieve VH-SAPO-11 has been studied by electron spin resonanace (ESR) and electron spin echo modulation (ESEM) spectroscopies to determine the vanadium locatin and interaction with various adsorbate molecules. As-synthsized VH-SAPO-11 contains only vanady1 species with distored octahral coordination. After calcinations in $O_2$ and exposure to moisture, only species A is observed with reduced intensities. Species A is suggested as a VO$(H_2O)_2^{2+$} complex coordinate to three framwork oxygen bonded to aluminum. When calcined, hydrate VH-SAPO-11 is dehydrated at elevated temperature, species A loses it water ligands and transforms to $VO^{2+}$ ions coordinated to three framework oxygens (species B). Species B reduces its intensities significantly after treatment with $O_2$at high temperature, thus suggesting oxidation of $v^{4+}$to $v^{5+}$. When dehydrated VH-SAPO-11 contacts with $D_2O$ at room temperature, the ESR signal of species A is observed. This species assumed as a $VO(O_f)_3(D_2O)_2$, by considering 3 framework oxygens. Adsorption of deuterated methanol on dehydrated VH-SAPO-11 results in another new vanadium species D, which is identified as a $VO(CD_{3}OH)$ complex. When deuterated ethanol is adsorbed on dehydrated VH-SAPO-11, another new vanadium species E identified as a $VO(C_{2}H_{5}OD)^{2+}$, is observed. When deuterated propanol is adsorbed on dehydrated VH-SAPO-11, a new vanadium species F identified as a $VO(C_{3}H_{7}OD)$, is observed. Possible coordination geometries of these various complexes are discussed.

• 한국결정성장학회지
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• 제15권2호
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• pp.79-85
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• 2005

수산화아파타이트 상용분말을 $1000{\sim}1350^{\circ}C$ 온도범위에서 2시간 동안 공기 중에서 하소한 다음, pH 7.4인 유사 생체용액에 넣고 $37^{\circ}C$에서 3일 또는 7일간 침적실험을 행하였다. 열분해에 따른 수산화아파타이트 분말의 용해 거동은 XRD, FTIR, TEM을 이용해 비교분석 하였다. $1200^{\circ}C$에서 하소된 수산화아파타이트 분말은 격자 내 $OH^-$ 이온들의 탈수로 인하여 OHAP(oxyhydroxyapatite, ($Ca_{10}(PO_4)_6O_x(OH)_{2-2x}$)로 전이하였다. $1350^{\circ}C$에서 수산화아파타이트 분말 일부가 ${\alpha}-TCP$(${\alpha}-tricalcium$ phosphate)와 TTCP (tetracalcium phosphate)로 열분해 되었다. 수산화아파타이트 분말의 열분해로 인해 생성된 ${\alpha}-TCP$, TTCP 및 비화학양론조성의 OHAP 조성들이 수산화아파타이트 분말의 표면용해를 진전시켰다.

• 한국통신학회논문지
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• 제29권8C호
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• pp.1113-1124
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• 2004

본 논문에서는 입력 영상을 실시간으로 압축 및 복원할 수 있는 하드웨어(hardware, H/W)의 구조를 제안하고 처리되는 영상의 보안 및 보호를 위한 워터마킹 기법(watermarking)을 제안하여 H/W로 내장하고자 한다. 영상압축과 복원과정을 하나의 FPGA 칩 내에서 처리할 수 있도록 요구되는 모든 영상처리 요소를 고려하였고 VHDL(VHSIC Hardware Description Language)을 사용하여 각각을 효율적인 구조의 H/W로 사상하였다. 필터링과 양자화 과정을 거친 다음에 워터마킹을 수행하여 최소의 화질 감소를 가지고 양자화 과정에 의해 워터마크의 소실이 없으면서 실시간으로 동작이 가능하도록 하였다. 구현된 하드웨어는 크게 데이터 패스부(data path part)와 제어부(Main Controller, Memory Controller)로 구분되고 데이터 패스부는 영상처리 블록과 데이터처리 블록으로 나누어진다. H/W 구현을 위해 알고리즘의 기능적인 간략화를 고려하여 H/W의 구조에 반영하였다. 동작은 크게 영상의 압축과 복원과정으로 구분되고 영상의 압축 시 대기지연 시간 없이 워터마킹이 수행되며 전체 동작은 A/D 변환기에 동기하여 필드단위의 동작을 수행한다. 구현된 H/W는 APEX20KC EP20K600CB652-7 FPGA 칩에서 69%(16980개)의 LAB(Logic Array Block)와 9%(28352개)의 ESB(Embedded System Block)을 사용하였고 최대 약 82MHz의 클록주파수에서 안정적으로 동작할 수 있어 초당 67필드(33 프레임)의 영상에 대해 워터마킹과 압축을 실시간으로 수행할 수 있었다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.204-209
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• 2004

This paper describes dynamic manipulability analysis of robotic arms moving in viscous fluid. The Manipulability is a functionality of manipulator system in a given configuration and under the limits of joint ability with respect to the tasks required to bt performed. To investigate the manipulability of underwater robotic arms, a modeling and analysis method are presented. The dynamic equation of motion of underwater manipulator is derived from the Lagrange - Euler equation considering with the hydraulic forces caused by added mass, buoyancy and hydraulic drag. The hydraulic drag term in the equation: is established as analytical form using Denavit - Hartenberg (D-H) link coordination of manipulator. Two analytical approaches based on Manipulability Ellipsoid are presented to visualize the manipulability of robotic arm moving in viscous fluid. The one is scaled ellipsoid which transforms the boundary of joint torque to acceleration boundary of end-effector by normalizing the torque in joint space while the other is shifted ellipsoid which depicts total acceleration boundary of end-effector by shifting the ellipsoid in work space. An analysis example of 2-link manipulator with proposed analysis scheme is presented to validate the method.