• 한국정보처리학회논문지
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• 제4권5호
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• pp.1277-1288
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• 1997

본 논문에서는 인체 문서 인식을 위한 전처리 과정인 개별 문자 추출 방법과 인식 방법에 대하여 논한다. 전처리에서는 접촉 문자(touching charadcter) 또는 겹친 문자 (overlaapped character) 등과 같이 추출이 곤란한 문자를 개별 문자로 추출하는 것이다. 기존의 문자 분리 방법에서는 투영((projection)에 의한 방법과 외곽선(edge)추척에 의한 방법 등을 사용하여 왔으나, 제안된 방법은 문자열 추출 후 한번의 투영으로 연결 화소를 이용하여 개별 문자를 추출한다. 인식을 위해서는 최대불록화 방법(Maximum Block Mehtod:MBM)을 이용하여 특징 추출을 한다. 최대불록화는 문자를 투영 중 처음 찾아진 점에서부터 최대한 불록을 확정 시키는 방법이다. 문자를 이루는 최대불록들을 직선 불록과 사선 불록으로 분리후 골격화 시킨다. 특히 한자 인식에서 기존의 상용 문자 인식기와 비교하여 향상된 인식율을 얻을 수 있다.

• 전자공학회논문지B
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• 제31B권11호
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• pp.116-123
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• 1994

본 논문에서는 직선특징을 포함한 2차원 패턴에 대하여 패턴의 이동, 회전, 크기변화에도 불변하게 인식할 수 있는 새로운 광/디지틀 패턴인식 방법을 제안하였다. 제시한 방법은 먼저 패턴의 직선특징을 Hough변환과 threshold과정을 통해서 추출한다. 두 번째로 추추된 특징에 본 논문에서 유도된 수식을 적용하여 불변성을 부여한다. 마지막으로 추출된 패턴의 불변특징을 신경회로망으로 학습시켜 패턴인식에 사용하였다. 제시한 방법의 유용성 확인을 위해 9개의 2차원 직선패턴으로 컴퓨터 모의실험을 수행하였으며, 결국 패턴의 이동, 회전, 크기변화에도 불변한 인식이 가능하였다.

• 드라이브 ㆍ 컨트롤
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• 제19권4호
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• pp.19-28
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• 2022

This paper introduces an automatic steering system for straight traveling capable of being mounted on drivable agricultural machinery which user can handle it such as a tractor, a transplant, etc. The modular automatic steering device proposed in the paper is composed of RTK GNSS, IMU, HMI, hydraulic valve, and wheel sensor. The path generation method of the automatic steering system is obtained from two location information(latitude and longitude on each point) measured by GNSS in advance. From HMI, a straight path(AB line) can be created by connecting latitude and longitude on each point and the device makes the machine able to follow the path. During traveling along the reference path, it acquires the real time position data every sample time(0.1s), compares the reference with them and calculates the lateral deviation. The values of deviation are used to control the steering angle of the machine using hydraulic valve mounted on the axle of front wheel. In this paper, Pure Pursuit algorithm is applied used in autonomous vehicles frequently. For the analysis of traveling characteristics, field tests were executed about these conditions: velocity of 2, 3, 4km/h which is applied to general agricultural work and ground surface of solid(asphalt) and weak condition(soil) such as farmland. In the case of weak ground state, two experiments were executed about no-load(without work) and load(with work such as plowing). The maximum average deviations were presented 2.44cm, 7.32cm, and 11.34cm during traveling on three ground conditions : asphalt, soil without load and with load(plowing).

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 추계학술대회논문집
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• pp.391-394
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• 2003

Laser direct writing process is developed 3rd harmonic Diode Pumped Solid State Laser with the near visible wavelength of 355 m sensitive polymer is irradiated by UV laser and developed using polymer solvent to obtain quasi-3D. It is important to reduce line width for image mode waveguides, so some investigations will be carried out in various conditions of process parameters such as laser power, writing speed, laser focus and optical properties of polymer. This process could be to fabricate a single mode waveguide without expensive mask projection method. Experimentally, the patterns of trapezoidal shape were manufactured into dimension of 8.4 mm width and 7.5 mm height. Propagation loss of straight waveguide measured 3 dB/cm at 1,550 nm.

• 한국정밀공학회지
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• 제17권2호
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• pp.211-219
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• 2000

This paper simulated surface grinding process with statistically simulated grinding wheel topography, considering ridge formation phenomenon when grain scratch workpiece. Wheel grain is modeled as hybrid sphere and cone. Grinding wheel characteristic was evaluated with stylus by expanding the scanning region of the profilometer from a straight line to a plane. Each grain's diameter and semi-angle are assumed as normal distribution, each grain's protrusion height from wheel plane is assumed gamma distribution. So grinding wheel is simulated with grain's position randomly distributed without overlapping. Ground surface is 3-dimensionally simulated considering ridge formation of workpiece by each grain's cutting, and then surface profile and surface roughness parameters are compared with real ground workpiece.

• Coupled systems mechanics
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• 제5권1호
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• pp.87-100
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• 2016

In this work, an improved semi-analytical technique is adopted to track the dynamic response of thin rectangular plates excited by sequential traveling masses. This technique exploits a so-called indirect definition of inertial interaction between the moving masses and the plate and leads to a reduction, in the equations of motion, of the number of time-varying coefficients linked to the changing position of the masses. By employing this optimized method, the resonance of the plate can be obtained according to a parametric study of relevant maximum dynamic amplification factor. For the case of evenly spaced, equal masses travelling along a straight line, the resonance velocity of the masses themselves is also approximately predicted via a fast methodology based on the fundamental frequency of the system only.

• 한국주거학회논문집
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• 제10권4호
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• pp.83-90
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• 1999

This study is concerned on the decorating design and method of handrail of the old residential houses. The method of studying is proceeding to select and survey the houses identified as the cultural properties that have the value of heritage in the handrail design. The conclusion as following ; Handrail play not only functional part but embellished part. The wood Handrails can be classified in two styles ; One "pyung"(평) style, another "keja"(계자) style. The former is composed of straight lines which looks simple. On the other hand, the latter contains the elavorated decoration which gives solid beauty. In conclusion, the characteristic of the handrail in Korean structure is found in the changing the sense of the lineal and curve beauty into the symmetrical line, and is fund in the variety of the high qualified details. Over its esthetic senses, the residents'hope and need for the goodness such as good omen, rich longevity and getting boys and formed as passive symbolic world, and the auspicious signed letters and the geometric and natural forms of plants, are expressed upon the decorating design of handrail. design of handrail.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.415-417
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• 2005

This paper proposes tracking control method using pseudo-backstepping control for wheeled mobile robots with nonholonomic constraints. First, the pseudo commands for forward linear velocity and angular velocity are chosen based on the kinematics. Then, the actual torque control inputs are designed to make the actual forward linear velocity and angular velocity follow the pseudo commands. Both semi-global practical posture(position and heading direction angle) stabilization and trajectory tracking are achieved for reference trajectories such as straight line and sinusoidal curve. The stability and performance analysed and numerical simulations are performed to confirm the effectiveness of the proposed scheme.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 춘계학술대회 논문집
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• pp.127-132
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• 1992

To relize the future intelligent robot the development of a special-purpose processor for a coordinate transformation is evidently challenging task. In this case the complexity of a hardware architecture strongly depends on the adopted algorithm. In this paper we have used an inverse kinemetics algorithm based on incremental unit computation method. This method considers the 3-axis articulated robot as the combination of two types of a 2-axis robot: polar robot and 2-axis planar articulated one. For each robot incremental units in the joint and Cartesian spaces are defined. With this approach the calculation of the inverse Jacobian matrix can be realized through a simple combinational logic gate. Futhermore, the incremental computation of the DDA integrator can be used to solve the direct kinematics. We have also designed a hardware architecture to implement the proposed algorithm. The architecture consists of serveral simple unitsl. The operative unit comprises several basic operators and simple data path with a small bit-length. The hardware architecture is realized byusing the EPLD. For the straight-line motion of the KAIST arm we have obtained maximum end effector's speed of 12.6 m/sec by adopting system clock of 8 MHz.

• 대한기계학회논문집A
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• 제24권7호
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• pp.1795-1800
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• 2000

One of the principal sources of vibration and noise in permanent magnetic machines is cogging torque, which is induced by interaction between the rotor poles and the stator teeth. For its analysis, using finite element analysis is very time consuming and the calculation of performance factors is extremely sensitive to the discretization. Especially, Maxwell stress tensor method is sensitive to the location of integral path. In this paper, a cogging permeance fuction is defined and replaced by the straight line. And it is assumed that the flux density acting on the stator's tooth side is the euqal to the flux density of the slot area. Using this definition and assumption, analytical calculation of cogging torque is presented and validated. And several reduction method is introduced.