• Journal of Mechanical Science and Technology
• /
• v.18 no.4
• /
• pp.573-581
• /
• 2004

A self-contained wall climbing robot, called MRWALLSPECT (Multi-functional Robot for WALL inSPECTion) II, is developed. It is designed for scanning external surfaces of gas or oil tanks with small curvature in order to find defects. The robot contains all the components for navigation in itself without any external tether cable. Although it takes the basic structure of the sliding body mechanism, the robot has its original characteristic features in the kinematic design with closed link mechanism, which is enabled by adopting a simple and robust gait pattern mimicking a biological system. By employing the proposed link mechanism, the number of actuators is reduced and high force-to-weight ratio is achieved. This paper describes its mechanism design and the overall features including hardware and software components. Also, the preliminary results of experiments are given for evaluating its performances.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1996.04a
• /
• pp.398-401
• /
• 1996

It is the aim of this study to introduce the application method for the new estimation system of deterioration caused performance decrement of exterior wall by infrared theromography. With this help of this trial test, the defect such as void and honeycomb of esveria wall can be shown easily. Espicially by selecting the weathering condition, it becomes easier to identify defect than with original image. It was confirmed that this trial monitoring system is very useful to identify the defect of exterior wall.

• Transactions of Materials Processing
• /
• v.6 no.6
• /
• pp.517-526
• /
• 1997

The purpose of this study is to investigate changes in the wall thickness of tube sinking and working forces by the upper bound method and ABAQUS code. The independent variables are ; workpiece material, original wall thickness of tube, die angle, friction, and reduction of diameter. The results indicate that these five variables are factors of the increase in wall-thickness and working forces. Three variables, a inner tube wall angle and two angles of the velocity discontinuous surfaces, are optimized in this proposed velocity field by the upper bound method. In this method, we can estimate the working forces and final tube thicknesses similar to actual forming process. Optimum process variables which are obtained by upper bound method are used in ABAQUS pre-model.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.8 no.5
• /
• pp.86-95
• /
• 2000

A modified spray impingement model has been developed, which is assessed against experiments for the impinging sprays on the small combustion chamber at various gas pressures. To investigate spray behaviors in the diesel combustion chamber, a transparent constant-volume chamber is made which is similar to the combustion chamber of the real diesel engine. The chamber is pressurized by N2 gas from 0 bar to 20 bar to find the effects of ambient pressures. The behaviors of spray injected into this chamber and dispersed after impingement on the cylinder wall is measured two-dimensionally using laser sheet Mie scattering method. The physical submodels have been properly modified to improve the prediction capability of original KIVA code to describe the spray behaviors after impingement on the curved cylinder wall. In terms of spray dynamics and evolution. numerical results give qualitatively good agreements with experimental data.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2003.09a
• /
• pp.74-81
• /
• 2003

During the 1995 Hyogoken-Nambu earthquake, many caisson-type quay walls in Kobe Port moved several meters towards the seaside due to liquefaction and subsequent ground flow, To investigate the mechanism of quay wall damage, we carried out the numerical simulation using the 2-D effective stress analysis. Input earthquake motions used for the analyses are original Dip wave and the component wave in each compact support of wavelet transformation. The results suggested that the shear failure occurred in the foundation soil underneath the caisson type quay wall due to the deformation of the caisson type quay wall.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.3
• /
• pp.329-335
• /
• 2008

This paper proposes a miniaturized half-circular-slot UWB antenna. Using an analysis of the neld patterns, we show that the original circular-slot UWB antenna operates on a series of multi-pole radiation based on $TE_n$ modes, and a perfect magnetic wall exists along an axis of symmetry on the antenna. Using the perfect magnetic wall we designed and fabricated the miniaturized UWB antenna on RF-60A substrate with t=0.64mm, ${\varepsilon}_r=6.15\;and\;tan\;{\delta}=0.0025$, which not only has the half size of the original but also maintains UWB characteristics. The measured gain of the miniaturized antenna is $-2.1{\sim}4.3dBi$, which is comparable with the gain, $-2.7{\sim}3.1dBi$, of the original circular-slot UWB antenna. The radiation pattern is also similar to that of the original antenna.

• Journal of architectural history
• /
• v.18 no.1
• /
• pp.31-49
• /
• 2009

Periodically, the Japanese Castle was created in the domestic of Japan and then 2 Invasions into Chosun was started. The Japanese Castle in the domestic of Japan was repaired several times by the building boom of castle before & after 2 invasions and so the initially-built type of castles was changed. Accordingly, there are much difficulties to understand the original shape of Japanese Castle. Through the Japanese Castle within Korea called as the fossil of Japanese Castle, I would like to examine & consider its building period and characteristics. The terminology called as [Two Side Stone's Wall] is that of castle which is not acknowledged in the Japanese Academic Circles. However, it means the two-fold wall of Japanese Castle which was widely applied to the fortification way in the Age of Japan Edo. The terminology of [Sori] says the stonework curve in the corner of Japanese Castle which is indicated best in the Japanese Castle. It calls the curve as like the fan frame. [Curb Stone's Wall] says the type of castle wall constructed with over 1 face in wall body of Japanese Castle. (1) About classifying the construction period of Japanese Castle, the curb stone's wall and the castle having no two side stone's wall must consider the building period as that of Japanese Invasion of Korea in 1592. If there was [Sori], the two-side stone's wall was used and the place which supported the documentary data, in particular, the place having the record of contraction is considered to be confirmed as the castle constructed in the period of Japanese Invasion of Korea in 1597. (2) The two-side-type stone's wall shown in the Modern Japanese Stone Castle is difficultly considered to be generated from the Japanese Castle at the period of Japanese Invasion of Korea in 1592 and in 1597. (3) The beautiful [Sori] shown in the Modern Japanese Stone Castle was started from the Japanese Castle of Korea at the period of Japanese Invasion of Korea in 1597. It is difficultly considered which its indication was firstly generated by the Chaesung-Folded Segment Structure.

• Journal of Chest Surgery
• /
• v.29 no.4
• /
• pp.472-476
• /
• 1996

Malignant flrous histiocytoma is a rare deep-seated pleomorphlc sarcoma, although its incidence Increasing. In this report, we present a case of a malignant fibrous histiocytoma, arising in the left chest wall in a 37-year-ol4 male patient. He underwent radical on bloc resection which include excision of tumor on left upper chest wall with resection of ribs from the first to third, left upper lo ectomy and chest wall reconstruction with Marled Mesh. However, he had local recurrence and distant metastasis within 12 months of the original operation. Malignant fibrous histiocytoma is an agrressive disease entity, with a propensity for early and distant spread.

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.12 no.2
• /
• pp.1-24
• /
• 2016

The original fracture criteria developed by Maxey/Kiefner for axial through-wall and surface-cracked pipes have worked well for many industries for a large variety of relatively low strength and toughness materials. However, newer line pipe steels have some unusual characteristics that differ from these older materials. One example is a test data that has demonstrated that X80 line-pipe with an axial through-wall-crack can fail at pressures about 30 percent lower than predicted with commonly used analysis methods for older steels. Thus, it is essential to review the currently available models and investigate the applicability of these models to newer high-strength line pipe materials. In this paper, the available models for predicting the failure behavior of axial-cracked pipes (through-wall-cracked and external surface-cracked pipes) were reviewed. Furthermore, the applicability of these models to high-strength steel pipes was investigated by analyzing limited full-scale pipe fracture initiation test results. Based on the analyzed results, the shortcomings of the available models were identified. For both through-wall and surface cracks, the major shortcomings were related to the characterization of the material toughness, which generally leads to non-conservative predictions in the J-T analyses. The findings in this paper may be limited to the test data that were consider for this study. The requisite characteristics of a potential model were also identified in the present paper.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.05a
• /
• pp.578-581
• /
• 2007

In this study, the seismic control performance of energy dissipation devices installed in a shear all-frame structure is investigated through nonlinear time history analysis of a 12-story building. Inelastic shear walls are modeled using the multiple vertical line element model (MVLEM) and inelastic columns and girders were modeled using fiber beam elements. For a seismic load increased by 38% compared to the design load, the seismic control performance was analyzed based on the results of a nonlinear time history analysis in terms of the inter-story drift, the story shear and the flexural strain. Friction type dampers was found to performs best if they are installed in the form of a brace adjacent to the shear wall with the friction force of 15 % of the maximum story shear force induced in the original building structure without dampers.