• Structural Engineering and Mechanics
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• v.63 no.3
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• pp.347-359
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• 2017

Blast resistant gates are required to be lightweight and able to mitigate extreme loading effect. This may be achieved through innovative design of a gate and its supporting frame. The first is well covered in literature while the latter is often overlooked. The design of supporting frame depends mainly on the boundary conditions and corresponding reaction forces. The later states the novelty and the aim of this paper, namely, the analysis of reaction forces in supporting structure of rectangular steel gates subjected to "far-field explosions". Flat steel plate was used as simplified gate structure, since the focus was on reaction forces rather than behaviour of gate itself. The analyses include both static and dynamic cases using analytical and numerical methods to emphasize the difference between both approaches, and provide some practical hints for engineers. The comprehensive study of reaction forces presented here, cover four different boundary conditions and three length to width ratios. Moreover, the effect of explosive charge and stand-off distance on reaction forces was also covered. The analyses presented can be used for a future design of a possible "blast absorbing supporting frame" which will increase the absorbing properties of the gate. This in return, may lead to lighter and more operational blast resistant gates.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.5
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• pp.566-582
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• 2018

A moored barge alongside quay can be influenced by a nearby passing ship and its ship-generated waves. In this study, a time-domain numerical method based on a three-dimensional potential flow solver is developed to investigate the passing ship problem with a moored barge alongside quay. Potential flows around the passing ship and the moored barge alongside a quay is directly solved by using a classical finite element method. Total computational meshes including a passing ship, a moored barge and a quay is updated at each step with an efficient re-mesh algorithm. To validate the developed numerical method, a conventional ship wave problem and a passing ship problem on the open sea has been solved and the solutions are compared with the existing data. Then, a series of numerical computations were carried out to investigate the passing ship effect on a moored barge alongside quay. The characteristics of the passing ship effects are studied with varying the simulation parameters such as passing ship speed, separation distance, wall distances and waves. Focus is made on hydrodynamic forces due to the passing ship effect and its ship waves.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.6
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• pp.96-101
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• 2020

In this paper, we present the results of our research to perform 3D laser scanning functions by adding a focusing lens to a conventional 2D laser scanner. For the optical design, the ray-tracing technique was used along with a total of four lenses as the variable incident focusing lens, the collimating lens, and the F-Theta lens. As design variables, the curvature of the incident focusing lens (Lens #1) was assumed to be us, l mm and sumed mm, and the incident angles were set at 0cidenus, l. In addition, the distance between the focusing lens and the collimating lens was set to vary from 5 mm to 15 mm. When the incident focal length was varied from 5 mm to 15 mm, the exit focal length was calculated to vary from 67.5 mm to 56.8 mm for the lens with R = 100 mm and from 108.5 mm to 99.0 mm for the lens with R = 150 mm. When the incident angle was 0°, the focal aberration was only slightly observable at 10㎛ in both the x- and y-direction. At 7.5° was the focal aberration of approximately 20~50㎛ was measured at 20㎛. To investigate the chromatic aberration of the designed optical device, the distortion of the focus was observed when the 550 nm beam was simulated on lens designed for a 980 nm wavelength.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.219-220
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• 2010

A new concept of ocean transport system, called mobile harbor, was introduced as a feasibility study in Korea in 2009. Target of the mobile harbor is a smart distance transport of containers with or without cargo handling cranes. Although the mobile harbor project has a lot of topics to deal with, this paper is to focus on only ship-to-ship stabilized mooring, which plays a key role in cargo handling. The ship-to-ship stabilized mooring system was developed and installed on beard a barge of LOA 32m and breadth 12m. The dockside tests as sea test were carried out so as to ascertain ascertained whether the systems can work well to control the barge's motion. The results of dockside test showed that the heave motion of the barge's motion can be reduced by more than 45%.

• Journal of Science of Art and Design
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• v.6
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• pp.267-287
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• 2004

The study of a new expression within Korean ink painting that meets the demands of the times has continued, resulting in various expressions with acrylics, handycoat, objects and installations, crossing over from traditional Korean painting techniques. A 'margin' was both a very important space and esthetical matter that expresses 'Ki', 'Distance', and 'Omission' in traditional sense when addressing Korean ink painting Its expression methods and concepts, however, have changed today. A 'margin' through Montage technique can be a significant example in understanding the expression methods of today's Korean ink painting. This is because the margins in Montage make the meaning of the work various and flourished and deeply construct the surface with a double-layered structure, instead of using a single layer. These 'margins' created by Montage are spaces where different images conflict, divide and continue with each other and where a reconciliation between different spaces is accomplished. Furthermore, they establish more vitality and truthfulness to life through both the images conflict and reconciliation. After the adoption of Post-modernism Art in Korean ink painting, the characteristics of the 'margin' in Montage style by the division of surface are an 'acceptant's participatory imaginative space'; where viewers fill the margins with their imaginations ; an 'abandoned space' ; where unnecessary parts are deleted for more live surface ; and a 'strategic space', where the work enriches the structure and contents of surface by using margins strategically.

• Journal of Educational Research in Mathematics
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• v.16 no.1
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• pp.59-78
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• 2006

As a theoretical background for this research, the literatures which focus on the rationale of teaching and learning of connecting with mathematics and science in calculus were investigated. And teaching and learning material of connecting with mathematics and science in calculus was developed. And then, based on the case study using this material, the research questions were analyzed in depth. Students could understand mean-velocity, instant-velocity, and acceleration in the experimenting process of constant acceleration movement. Also Students could understand fundamental ideas that instant-velocity means slope of the tangent line at one point on the time-displacement graph and rate of distance change means rate of area change under a time-velocity graph.

• Journal of electromagnetic engineering and science
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• v.12 no.1
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• pp.26-31
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• 2012

We have proposed a metamaterial lens that enables sub-wavelength focusing, which is shorter than an operating wavelength. Our lens is a two dimensional array of a unit cell consisting of a metallic dual-plate printed on a dielectric substrate. The unique dual-plate structure provides negativeness both in permittivity and permeability, with no help from conventional additional structures, which are normally printed on the opposite of metallic patterns. Therefore, we can focus a source (or an image) in a tiny distance shorter than the free space wavelength (${\lambda}$) at the frequencies of interest. Furthermore, since the proposed geometry does not need separate supplementary structures to acquire negative permittivity or permeability, our lens is much simpler than conventional metamaterial lenses, which is a strong point in practical applications. We have validated sub-wavelength focusing ability in a 6 GHz frequency band through an experiment of near field scanning, which provided the width of about 0.19 ${\lambda}$ at a half maximum of a peak value of an measured image. The width of the focused image through the lens is more than 4 times shorter than that without the lens, which confirms the validity of our design approach.

• Journal of the Ergonomics Society of Korea
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• v.30 no.4
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• pp.563-569
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• 2011

Objective: This study focuses on the effects of pre-cues informing the location of upcoming visual stimulus on finger movement response in the context of control-on-display interfaces. Background: Previous research on pre-cues focus on attention allocation and motion studies were limited to indirect control conditions. The design of this study aimed to collect data on the exact landing point for finger-tap responses to a given visual stimulus. Method: Controlled visual stimuli and tasks were presented on a UI evaluation system built using mobile web standards; response accuracy and response time were measured and collected as appropriate. Among the 16 recruited participants, 11 completed the experiment. Results: Providing pre-cue on the location of stimulus affected response time and response accuracy. The response bias, which is a distance from the center of stimulus to the finger-tap location, was larger when the pre-cue was given during a one-handed operation. Conclusion: Given a pre-cue, response time decreases, but with accuracy penalized. Application: In designing touch-screen UI's - more strictly, visual components also acting as controllers - designers would do well to balance human perceptual and cognitive characteristics strategically.

• Journal of Korea Multimedia Society
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• v.4 no.3
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• pp.270-279
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• 2001

Since most program execution time is spent in the loop structure, extracting parallelism from sequential loop programs hale been focused. But, most programs hare implicit parallelism of interprocedure. This paper presents a generalized Parallelism extraction in loop\ulcorner with procedure calls. Most parallelization of loops with Procedure calls just focus on the uniform code which data dependency distance is constant. We presents algorithms which can be applied with uniform code, nonuniform code, and complex code. The proposed algorithm, loop extraction, loop embedding and procedure cloning transformation methods evaluate using CRAY-T3E. The result of performance evaluation is that proposed algorithm is an effect.

• Korean Journal of Human Ecology
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• v.14 no.3
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• pp.491-504
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• 2005

This research studies the residential environment of the elderly and its trend. Our main focus is on the residential condition and its type between parents and their child/ren in korea which has already entered the aging society. The results are as follows: (1) This paper finds that the residence type of the households with elderly people becomes multifarious, as in a two-generation household, a couple and their single child, a couple family, etc. (2) The parents living separately from their child/ren account for 63.3%, which is becoming predominant in the residence type of the elderly. On the other hand, those living with their child/ren take up merely 24.5%. Thus, we can infer that the number of the parents with the former type is on the increase. (3) The residence type in reality is different from the one intended by elderly people, so we can estimate future change in the residence type. (4) The residence type varies, as in living together with young family, living separately from young family, separation at a distance, etc. In conclusion, we need appropriate living programs for each various residence type between elderly people and their children.