• Journal of the Society of Naval Architects of Korea
• /
• v.30 no.1
• /
• pp.73-86
• /
• 1993

This paper describes a potential-based panel method for the prediction of steday performance of a marine propeller operating in a uniform oncoming flow. An integral equation with unknown dipole strengths is formulated by distributing the normal dipoles and/or sources on the blade and hub surfaces and the wake sheet, and is solved numerically upon discretization. A hyperboloidal panel has been adopted to compute the potential induced by a normal dipole on a non-planar quadrilateral panel. The Kutta condition is satisfied by iteratively annulling the pressure jumps at the trailing edge. Extensive convergence tests are carried out, and the influence of the wake model upon performance is studied. Predicted performance is shown to correlate well with the experiments.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.4 no.1
• /
• pp.34-44
• /
• 1992

A numerical model using Hybrid Element Method(HEM) is presented for the prediction of wave agitations in a harbor which are induced by the intrusion and transformation of incident short-period waves. A linear mild-slope equation including bottom friction is used as the governing equation and a partial absorbing boundary condition is used on solid boundaries. Functional derived in the present paper is based on the Chen and Mei(1974)'s concept which uses finite element net in the inner region and analytical solution of Helmholtz equation in the outer region. Final simultaneous equations are solved using the Gaussian Elimination Method. The model appears to be reasonably good from the comparison of numerical calculation with hydraulic experimental results of short-wave diffraction through a breakwater gap(Pos and Kilner, 1987). The problem of requring large computational memory could be overcome using 8-noded isoparametric elements.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.3
• /
• pp.847-852
• /
• 2010

Text in natural images has a various and important feature of image. Therefore, to detect text and extraction of text, recognizing it is a studied as an important research area. Lately, many applications of various fields is being developed based on mobile phone camera technology. Detecting edge component form gray-scale image and detect an boundary of text regions by local standard deviation and get an connected components using Euclidean distance of RGB color space. Labeling the detected edges and connected component and get bounding boxes each regions. Candidate of text achieved with heuristic rule of text. Detected candidate text regions was merged for generation for one candidate text region, then text region detected with verifying candidate text region using ectilarity characterization of adjacency and ectilarity between candidate text regions. Experctental results, We improved text region detection rate using completentary of edge and color connected component.

• Journal of the Korean GEO-environmental Society
• /
• v.15 no.3
• /
• pp.41-48
• /
• 2014

Experimental study of sedimentation and self-weight consolidation has been primary research area in dredged soil. However, good quality of the dredged soil and minimum water pollution caused by the pumping of reclaimed soil require intensive study of the flow characteristics of dredged material due to dumping. In this study, continuity and the equilibrium equations for mass flow assuming single phase was derived to simulate mass flow in dredged containment area. To optimize computation and modeling time for three dimensional geometry and boundary conditions, depth integration is applied to governing equations to consider three dimensional topography of the site. Petrov-Galerkin formulation is applied in spatial discretization of governing equations. Generalized trapezoidal rule is used for time integration, and Newton iteration process approximated the solution. DG and CDG technique were used for weighting matrix in discontinuous test function in dredged flow analysis, and numerical stability was evaluated by performed a square slump simulation. A comparative analysis for numerical methods showed that DG method applied to SU / PG formulation gives minimal pseudo oscillation and reliable numerical results.

• Journal of Sensor Science and Technology
• /
• v.10 no.5
• /
• pp.304-313
• /
• 2001

In this research, we investigate wet-etching properties of GaAs in $NH_4OH-H_2O_2-H_2O$, and develop the fabrication method of GaAs microstructures with rectangular cross section using (001) GaAs substrate. For obtaining wet-etching properties with respect to crystallographic orientation, the etch rates and cross-section etch profiles of (001) GaAs with 16 different compositions and the undercut rates with 5 different compositions are measured using $NH_4OH-H_2O_2-H_2O$ mixed solutions. From these experimental data, a new GaAs micromachining method in bulk (001) GaAs is proposed, and used to fabricate a released microbridges with a rectangular cross section. The developed GaAs micromachining method can be very useful for low-loss, highly-tunable capacitors for RF components and for integration with GaAs optical components.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.37 no.5
• /
• pp.64-77
• /
• 2009

In landscape architecture, the pursuit of pluralism requires diverse expression based on cultural and philosophical differences. Landscape architects impart social purposes and spatial relationships to the contemporary generation by providing particular environments that reflect the culture of the day. Particularly, landscape architects reflect contemporary art in their design works and express the characteristics of the arts of the day in real spaces. Historically they have sought motives from all fields of art. The plastic concept in landscape design is based specifically on paintings that directly influence spatial composition. Minimalism in landscape architecture contributes to the formation of artistic characteristics that can be explained to improve artistry in landscapes as aesthetic objects, which were eliminated in the modernist era, and to realize contemporary art. By interpretively studying design works, therefore, this study reveals plastic concepts' influence on landscape design affected by minimalist art. The characteristics of plastic concepts in minimalist landscape design can be summarized as follows. First, the reduction of Minimalist Landscape is meant for viewers to immediately understand a work's identity and to easily perceive its intention by using design language implied by the pure geometric forms such as circles, triangles and squares. Second, the extension intends to seek internal order by connecting design elements mutually and externally to provide visual direction by adopting linear expression. Third, the flatness that defines meaningless space tends to overlay additional elements on a flattened site to induce the perception of a sequence of landscapes and to patternize pavement to improve its visual image. Finally, seriality has two characteristics: to make centrality in space and to compose by repeating formative elements and materials based on the pursuit of a site's totality, rather than an individual space's originality.

• The Journal of the Acoustical Society of Korea
• /
• v.35 no.4
• /
• pp.303-309
• /
• 2016

This paper proposes a novel approach to the problem of audio signal clustering using a stacked autoencoder. The proposed stacked autoencoder learns an efficient representation for the input signal, enables clustering constituent signals with similar characteristics, and therefore the original sources can be separated based on the clustering results. STFT (Short-Time Fourier Transform) is performed to extract time-frequency spectrum, and rectangular windows at all the possible locations are used as input values to the autoencoder. The outputs at the middle, encoding layer, are used to cluster the rectangular windows and the original sources are separated by the Wiener filters derived from the clustering results. Source separation experiments were carried out in comparison to the conventional NMF (Non-negative Matrix Factorization), and the estimated sources by the proposed method well represent the characteristics of the orignal sources as shown in the time-frequency representation.

• Cartoon and Animation Studies
• /
• s.18
• /
• pp.1-16
• /
• 2010

As manga is a genre characterized by combined use of letters and pictures, visual expression, that is style, is one of the most important representative elements, even beyond the structuring of the story. Shojo Manga (lit. Young girl's Manga) in particular is distinguished by visual style clearly differentiated from other manga genres. Shojo Manga uses a variety of unique techniques that cannot be found in other manga genres. The use of starry eyes in the depiction of the characters, taller than life characters, and the creative use of frames which disregard the traditional square shape are some examples. Therefore, the question arises of by whom and when such visual characteristics in Shojo Manga were created. This paper will analyze the figure of Nakahara Junichi (1913-1983), illustrator of Shojo magazines active between the 1930's and 1950's, and who as it has been stated in previous research, influenced the splendorous illustrations of Shojo Manga. Therefore, I will look for the commonalities and differences between Shojo Manga and Nakahara's oeuvre, shedding light on the origins of Shojo Manga and attempting to theorize the relationship existing between them.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.34 no.9
• /
• pp.45-52
• /
• 2006

In this study, a nonlinear control by feedback linearization method, one of nonlinear control schemes based on the nonlinear model, is proposed to suppress the flutter of a supersonic composite panel using piezoelectric materials. Most of the previous panel flutter controllers are the LQR(Linear Quadratic Regulator) which is based on the linear model. A nonlinear feedback linearizing controller proposed in this study considers the nonlinear characteristics of the system model. We use the actuator implemented by piezoceramic PZT. Using the principle of virtual displacements and a finite element discretization with the conforming four-node rectangular element, we first derive the discretized dynamic equations of motion, which are transformed into a nonlinear coupled-modal equations of motion of state space form. The effectiveness of the proposed method is also compared with the LQR based on the linear model through numerical simulations in the time domain using the Newmark method.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.21 no.6
• /
• pp.705-711
• /
• 2011

This paper proposes an effective algorithm of license plate recognition for industrial applications. By applying Canny edge detection on a vehicle image, it is possible to find a connected rectangular, which is a strong candidate for license plate. The color information of license plate separates plates into white and green. Then, OTSU binary image processing and foreground neighbor pixel propagation algorithm CLNF will be applied to each license plates to reduce noise except numbers and letters. Finally, through labeling, numbers and letters will be extracted from the license plate. Letter and number regions, separated from the plate, pass through mesh method and thinning process for extracting feature vectors by X-Y projection method. The extracted feature vectors are compared with the pre-learned weighting values by backpropagation neural network to execute final recognition process. The experiment results show that the proposed license plate recognition algorithm works effectively.