• JSTS:Journal of Semiconductor Technology and Science
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• v.9 no.4
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• pp.225-232
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• 2009

An analytical compact model for the asymmetric lightly doped Double Gate (DG) MOSFET is presented. The model is developed using the Lambert Function and a 2-dimensional (2-D) parabolic electrostatic potential approximation. Compact models of the net charge and channel current of the DG-MOSFET are derived in section 2. Results for the channel potential and current are compared with 2-D numerical data for a lightly doped DG MOSFET in section 3, showing very good agreement.

• Wind and Structures
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• v.21 no.1
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• pp.63-84
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• 2015

The shape of a tall building has significant impact on wind force generation and wind-induced dynamic response. To study the effect of recessed cavities, wind excitations on a wind-tunnel model of an H-section tall building were compared with those on a square-section building model. Characteristics of the fluctuating wind pressures on the side faces of the two tall buildings and their role in the generation of crosswind forces on the buildings were investigated with the space-time statistical tool of proper orthogonal decomposition (POD). This paper also compares the use of different pressure data sets for POD analysis in situations where pressures on two different surfaces are responsible for the generation of a wind force. The first POD mode is found to dominate the generation of crosswind excitation on the buildings.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.431-436
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• 2006

The latest system of GIS has been changing from 2 dimension to 3 dimension. According to the rapid growth of the fields linked to 3D GIS, 3D GIS has variously affected the public field, the national defense field, and the industrial field. This study estimated sight distance safety of curve section considering the environmental impact based on 3D GIS. Sight distance is calculated from the relation between road which keeps the three-dimension character and driver gaze, so it needs to consider both plane and vertical ior the accurate measuring. This study made analysis of the sight distance through considering the environmental impact with driving simulation of design speed 80km/h and running speed 60-120km/h.

• Journal of the Korean Professional Engineers Association
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• v.34 no.1
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• pp.27-34
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• 2001

On 16Dec. 1999, It was 100 years since the opening the first railroad section of 33.2km on Sep. 1899, Korea High Speed Railroad had a successful trial run of 200km/h on test track section. And the test speed 300km/h was achieved an 28 June 2000 during continuous commissioning. In the 21st century, the High Speed Railroad will be opened commercially in Korea and will contribute to technical development. Now, it is necessary to re-evaluate the role of railroad in modern society and to activate the railroad system. Ultimately, the competitive power of nation will be strengthened with energy saving, reduction of pollution and transportation cost. It conclusion the railroad system have to be expaned about 50% of total transportation to make preparations for reopening of Eurasia silk route through KyungEu railroad connection.

• Structural Engineering and Mechanics
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• v.9 no.2
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• pp.169-180
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• 2000

An optimization procedure has been prescribed for the minimum weight design of symmetrical parabolic arches subjected to arbitrary loading. The cross section is assumed to be a symmetrical box section with variable depth and flange areas. The webs are unstiffened and have constant thickness. The proposed sequential, iterative search technique determines the optimum geometrical configuration of the parabolic arch which includes the optimum depth profile and the optimum lengths and areas of the required flange plates corresponding to the prescribed number of curtailments. The study shows that the optimum value of rise to span ratio (h/L) of a parabolic arch is maximum at 0.41 for uniformly distributed loading over the entire span. For any other loading, the optimum value of h/L is less than 0.41.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.199-202
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• 2009

In roll forming process, a sheet metal is continuously progressively formed into a product with required cross-section and longitudinal shape, such as a circular tube with required diameter, wall-thickness and straightness, by passing through a series of forming rolls in arranged in tandem. Tn this process, each pair of forming rolls installed in a forming machine play a particular role in making up the required cross-section and longitudinal shape of the product. In recent years, that process is often applied to the bumper rail in the automotive industries. In this study, a optimal Front Bumper Beam manufacturing technology, model deign and proper roll-pass sequences can be suggested by forming number of roll-pass and bending angle. And also effects of the process parameters on the final shape formed by roll forming defects were evaluated.

• Journal of Wetlands Research
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• v.4 no.2
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• pp.13-22
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• 2002

Difference of the inset diversity and community structures between the bog Hwaeom-neup and its surrounding forest of Mt. Wonhyo-san located at Yangsan were investigated. Overall 15 orders, 87 families, 204 genera and 233 species were identified. Hydrophilic Harpalidae species were observed in small number at the bog, while the insect species representing hardwood forest were also collected at the bog. Species diversity was relatively higher at the forest (H'=4.80) than at the bog (H'=4.10). The dominant species was Diplous depressus (Gebler) both at bog as well as at forest. Ground-walking Coleoptera as Carabus sternbergi stembergi Roeschke, Damaster jankowskii jankowskii (Oberthur) and D. depressus was spread from forest into bog. Longhorn beetles Leptura arcuata Panzer and Chlorophorus diadema (Motschulsky) being characteristic species of shrub forest were also observed spreading into bog. It was consequently suggested that the bog was in part progressed into dry succession and its boundary was not clearly defined with forest at least upon the structure of insect commnunity.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.4
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• pp.330-340
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• 2018

In the present works, the High-speed Cavitation Tunnel (HCT) has been designed and manufactured to have the large test section to conduct various supercavitation experiments. The large amount of air ventilated behind a cavitator produces lots of tiny bubbles, which prevent clear observation of supercavitation at the test section. To collect small bubbles effectively, a bubble collecting section of large volume is equipped upstream of the test section. HCT has the test section dimension of $0.3^H{\times}0.3^W{\times}3.0^L\;m^3$ and provides maximum flow speed of 20.4 m/s at the test section. The blockage and Froude effects on the ventilated supercavitation are investigated successfully at the test section. The basic studies such as the supercavitation evolution, drag measurements and cavity shape extraction with air flow rate are also carried out in HCT.

• Steel and Composite Structures
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• v.27 no.3
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• pp.337-353
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• 2018

In previous weak-axis moment connection tests, brittle fracture always initiated near the edge of the beam flange groove weld due to force flow towards the stiffer column flanges, which is the opposite pattern as strong-axis moment connections. As part of the China NSFC (51278061) study, this paper tested two full-scale novel weak-axis reduced beam section moment connections, including one exterior frame connection specimen SJ-1 under beam end monotonic loading and one interior frame joint specimen SJ-2 under column top cyclic loading. Test results showed that these two specimens were able to satisfy the demands of FEMA-267 (1995) or ANSI/AISC 341-10 (2010) without experiencing brittle fracture. A parametric analysis using the finite element software ABAQUS was carried out to better understand the cyclic performance of the novel weak-axis reduced beam section moment connections, and the influence of the distance between skin plate and reduced beam section, a, the length of the reduced beam section, b, and the cutting depth of the reduced beam section, c, on the cyclic performance was analyzed. It was found that increasing three parametric values reasonably is beneficial to forming beam plastic hinges, and increasing the parameter a is conducive to reducing stress concentration of beam flange groove welds while increasing the parameters b and c can only reduce the peak stress of beam flange groove welds. The rules recommended by FEMA350 (2000) are suitable for designing the proposed weak-axis RBS moment connection, and a proven calculation formulation is given to determine the thickness of skin plate, the key components in the proposed weak-axis connections. Based on the experimental and numerical results, a design procedure for the proposed weak-axis RBS moment connections was developed.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.1
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• pp.1-9
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• 1992

The author has examined the response of sting fish, Sebastes inermis and black porgy, Acanthopagrus schlegelii to the attraction lamps(1 W) line in an experimental water tank(550 L$\times$ 58 W $\times$ 73H cm). Attraction lamp was set up at intervals of 55 cm for each section. The frequency rate was investigated at the illuminated section in accordance with the intervals of lighting on and putting out that was 1, 3 and 5 minutes under two conditions of light stimulus. The results are as follows: 1. Frequency rate at the last section when each of the attraction lamps was gradually switched on and off: (1) Sting fish was 27.2 % in case of 3 minutes interval, and 17.4 % in 1 minutes interval, and 15.8 % in 5 minutes interval. (2) Black porgy was 28.5 % in case of 5 minutes interval, and 25.8 % in 3 minutes interval, and 12.0 % in 1 minutes interval. 2. Distribution of fish at the illuminated section when each of the attraction lamps was gradually switched off after they were switched on all at once: (1) Sting fish was much gathered in the section adjacent to the extinguished section under the condition of 1 and 3 minutes interval, and not regular trend under 5 minutes interval. (2) Black porgy was much gathered last section under the condition of 1 and 3 minutes interval, and almost evenly distributed under 5 minutes interval. 3. Each of the attraction lamps was gradually switched off after they were switched on all at once, and only the last one was on: (1) The frequency rate of Sting fish was 27.2 % in case of 5 minutes interval, and 16.0 % in 1 minute interval, and 8.0 % in 3 minutes interval. (2) The frequency rate of Black porgy was 10.7 % in case of 1 minute interval, and 8.9 % in 3 minutes interval, and 0.8 % in 5 minutes interval.