• Title/Summary/Keyword: stroke shapes

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Dynamic Computed Tomography based on Spatio-temporal Analysis in Acute Stroke: Preliminary Study (급성 뇌졸중 환자의 시공간 분석 기법을 이용한 동적 전산화 단층 검사: 예비 연구)

  • Park, Ha-Young;Pyeon, Do-Yeong;Kim, Da-Hye;Jung, Young-jin
    • Journal of radiological science and technology
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    • v.39 no.4
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    • pp.543-547
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    • 2016
  • Acute stroke is a one of common disease that require fast diagnosis and treatment to save patients life. however, the acute stroke may cause lifelong disability due to brain damage with no prompt surgical procedure. In order to diagnose the Stroke, brain perfusion CT examination and possible rapid implementation of 3D angiography has been widely used. However, a low-dose technique should be applied for the examination since a lot of radiation exposure to the patient may cause secondary damage for the patients. Therefore, the degradation of the measured CT images may interferes with a clinical check in that blood vessel shapes on the CT image are significantly affected by gaussian noise. In this study, we employed the spatio-temporal technique to analyze dynamic (brain perfusion) CT data to improve an image quality for successful clinical diagnosis. As a results, proposed technique could remove gaussian noise successfully, demonstrated a possibility of new image segmentation technique for CT angiography. Qualitative evaluation was conducted by skilled radiological technologists, indicated significant quality improvement of dynamic CT images. the proposed technique will be useful tools as a clinical application for brain perfusion CT examination.

The Effect of the Gate Shape on the Microstructure of the Grain Size Controlled Material (게이트 형상이 결정립 제어 소재의 미세조직에 미치는 영향)

  • Jung Y.S.;Seo P. K.;Kang C. G.
    • Transactions of Materials Processing
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    • v.14 no.1 s.73
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    • pp.49-56
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    • 2005
  • In the semi-solid die casting process, an important thing is the flow behavior of semi-solid materials. The flow patterns of the semi-solid material can make the defects during die filling. To control the flow patterns is very important and difficult. In this paper, the flow behavior of the semi-solid A356 alloy material during die filing at various die gate shapes has been observed with the grain size controlled material. The effect of the gate shape on the die filling characteristics was investigated. The filling tests in each plunger stroke were experimented, and also simulated on the semi-solid material die casting process by MAGMAsoft. According to the filling tests and computer simulation, the effect of the gate shape on liquid segregation has been investigated.

Preform Design of Backward Extrusion Based on Inference of Analytical Knowledge (해석적 지식 추론을 통한 후방 압출푸의 예비 성형체 설계)

  • 김병민
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1999.03b
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    • pp.84-87
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    • 1999
  • This paper presents a preform design method that combines the analytic method and inference of known knowledge with neural network. The analytic method is a finite element method that is used to simulate backward extrusion with pre-defined process parameters. The multi-layer network and back-propagation algorithm are utilized to learn the training examples from the simulation results. The design procedures are utilized to learn the training examples from the simulation results. The design procedures are two methods the first the neural network infer the deformed shape from the pre-defined processes parameters. The other the network infer the processes parameters from deformed shape. Especially the latest method is very useful to design the preform From the desired feature it is possible to determine the processes parameters such as friction stroke and tooling geometry. The proposed method is useful for shop floor to decide the processes parameters and preform shapes for producing sound product.

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The Recognition of Korean Character Using Preceding Layer Driven MLP (Preceding Layer Driven 다층 퍼셉트론을 이용한 한글문자 인식)

  • 백승엽;김동훈;정호선
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.28B no.5
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    • pp.382-393
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    • 1991
  • In this paper, we propose a method for recognizing printed Korean characters using the Preceding Layer Driven multi-layer perceptron. The new learning algorithm which assigns the weight values to an integer and makes use of the transfer function as the step function was presented to design the hardware. We obtained 522 Korean character-image as an experimental object through scanner with 600DPI resolution. The preprocessing for feature extraction of Korean character is the separation of individual character, noise elimination smoothing, thinnig, edge point extraction, branch point extraction, and stroke segmentation. The used feature data are the number of edge points and their shapes, the number of branch points, and the number of strokes with 8 directions.

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High Speed Tool Feed System by the Mechanism of Ball Screw and Servo Motor (볼 나사와 서보모터 메커니즘에 의한 고속 TOOL 이송장치)

  • 김성식;김경석
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.11
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    • pp.76-82
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    • 1998
  • In this study, the Ball screw and Servo motor Mechanism is considered as a High Speed Tool Feed System for the machining of a piston of a reciprocating engine. For the machining of a piston, that shapes oval, high speed servo mechanism is needed as a positioning of a cutting tool, and the stroke of tool is 0.1 mm ~ 1 mm. Ball screw and servo motor Mechanism is available very much because this mechanism is used widely in general machine. This Mechanism has been designed with the use of the decrease in mass and partial wear of the ball screw for high speed positioning of tool. Also the periodic learning control method with the inverse transfer function compensation has been applied to the positioning control for the high accuracy positioning of tool. These applications lead the achievement of the machining of a piston with an accuracy of 5${\mu}{\textrm}{m}$ at 2500 rpm in CNC turning.

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Study on the Design of a Novel Adaptive Gripper (적응형 그리퍼 설계 연구)

  • Kim, Gi Sung;Kim, Han Sung
    • Journal of the Korean Society of Industry Convergence
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    • v.22 no.3
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    • pp.325-335
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    • 2019
  • In this paper, a novel adaptive gripper with underactuation is presented, which can change its configuration to parallel or power grip mode according to object shapes. Differently from the commercial adaptive gripper by RobotiQ, the proposed gripper includes an actual parallelogram inside a five-bar mechanism, which allows the free selection of actuator locations and can reduce actuation torques effectively. The forward and inverse kinematics for two grip modes and statics analysis have been analyzed. From the comparative design, the proposed gripper has about 20% smaller size, 3.7% larger stroke, and 30.5% smaller average actuation torque than the commercial one.

Curvature stroke modeling for the recognition of on-line cursive korean characters (온라인 흘림체 한글 인식을 위한 곡률획 모델링 기법)

  • 전병환;김무영;김창수;박강령;김재희
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.33B no.11
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    • pp.140-149
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    • 1996
  • Cursive characters are written on an economical principle to reduce the motion of a pen in the limit of distinction between characters. That is, the pen is not lifted up to move for writing a next stroke, the pen is not moved at all, or connected two strokes chance their shapes to a similar and simple shape which is easy to be written. For these reasons, strokes and korean alphabets are not only easy to be changed, but also difficult to be splitted. In this paper, we propose a curvature stroke modeling method for splitting and matching by using a structural primitive. A curvature stroke is defined as a substroke which does not change its curvanture. Input strokes handwritten in a cursive style are splitted into a sequence of curvature strokes by segmenting the points which change the direction of rotation, which occur a sudden change of direction, and which occur an excessive rotation Each reference of korean alphabets is handwritten in a printed style and is saved as a sequence of curvature strikes which is generated by splitting process. And merging process is used to generate various sequences of curvature strikes for matching. Here, it is also considered that imaginary strokes can be written or omitted. By using a curvature stroke as a unit of recognition, redundant splitting points in input characters are effectively reduced and exact matching is possible by generating a reference curvature stroke, which consists of the parts of adjacent two korean alphasbets, even when the connecting points between korean alphabets are not splitted. The results showed 83.6% as recognition rate of the first candidate and 0.99sec./character (CPU clock:66MHz) as processing time.

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Application of IDA Method for Hull Plate Forming by Multi-Point Press Forming (다점 프레스를 이용한 곡면 성형의 가공 정보 산출을 위한 IDA방법)

  • Yoon, Jong-Sung;Lee, Jang-Hyun;Ryu, Cheol-Ho;Hwang, Se-Yun;Lee, Hwang-Beom
    • Journal of Ocean Engineering and Technology
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    • v.22 no.6
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    • pp.75-82
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    • 2008
  • Flame bending has been extensively used in the shipbuilding industry for hull plate forming In flame bending it is difficult to obtain the desired shape because the residual deformation dependson the complex temperature distribution and the thermal plastic strain. Mechanical bending such as reconfigurable press forming multi-point press forming or die-less forming has been found to improve the automation of hull plateforming because it can more accurately control the desired shape than line heating. Multi-point forming is a process in which external forces are used to form metal work-pieces. Therefore it can be a flexible and efficient forming technique. This paper presents an optimal approach to determining the press-stroke for multi-point press forming of curved shapes. An integrated configuration of Finite element analysis (FEA) and spring-back compensation algorithm is developed to calculate the strokes of the multi-point press. Not only spring-back is modeled by elastic plastic shell elements but also an iterative algorithm to compensate the spring-back is applied to adjust the amount of pressing stroke. An iterative displacement adjustment (IDA) method is applied by integration of the FEA procedure and the spring-back compensation work. Shape deviation between the desired surface and deform£d plate is minimized by the IDA algorithm.

Improvement of Attention and Memory of Stroke Patient Using Smart Phone Applications : Single Case Study (스마트폰 어플리케이션을 이용한 뇌졸중 환자의 집중력과 기억력 증진: 단일 사례연구)

  • Lee, In-Seon
    • Therapeutic Science for Rehabilitation
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    • v.3 no.1
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    • pp.57-65
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    • 2014
  • Objective : In this study, to investigate the effect of Attention and Memory using a smart phone application intervention for stroke patients. Methods : single-subject experimental research was conducted using an ABA design. During the study, subject was applied to a total of 20 sessions with five times baseline, ten times intervention line, five times re-baseline. baseline and re-baseline did not have a separate intervention. During the intervetion line was trained by the application 'Master of memory(Numbers, Shapes, Fruits mode)' and 'Matching cute animals'. All sessions were evaluated an Attention and Memory using by 'Master of memory(Random mode)' and 'Memory free(Picture memory)' application. The resulting data was presented in graphs and descriptive statistics. Results : Implemented in all session, Attention and Memory assessment results showed the improvement of Attention and Memory in intervention line. Assessments conducted before and after the intervention, showed the improvement of Attention and Memory after the evaluation of interventions respectively. Conclusion : The results of this study are expected to be clinically useful. Follow-up studies on smart phone application intervention are needed for more targeted sampling study and conducted over a long period of time.

Influence of Compression Ratio on Engine Performance in Heavy-duty LPG Single-cylinder Engine (대형 LPG 단기통엔진에서 압축비가 기관성능에 미치는 영향)

  • 김진호;최경호
    • Journal of Energy Engineering
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    • v.11 no.2
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    • pp.160-165
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    • 2002
  • The heavy-duty LPG-fueled single cylinder engine was designed and developed as a fundamental equipment for analyzing combustion processes and emission performances. The cylinder head and the piston crown were modified to fire the LPG in the engine. The flywheel was also fabricated to minimize the vibration of the single cylinder engine. The size of bore and stroke of the tested engine are 130 mm and 140 mm, respectively. Compression ratios were varied 8 to 9 with different piston crown shapes. The developed single cylinder engine operates at 1,000 rpm for this work. The major conclusions of this work are; (1) the power of the developed engine was peaked at the condition of equivalence ratio 1.0 at three different compression ratios; (2) the power is slightly increased with the increase of compression ratio; (3) the optimum ignition timing is retarded with the increase of compression ratio ranged 2 to 10 crank angle.