• Journal of the Korean GEO-environmental Society
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• v.14 no.3
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• pp.5-11
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• 2013

The primary objective of this research is to evaluate the behavior of a bridge substructure subjected to scouring during flood. A finite element (FE) study was carried out on a substructure modeled using the standard section specified for highway bridges. The three-dimensional FE model consists of non-linear springs with tri-axial load capacities at the base in order to consider the loss of bearing capacity of the substructure by local scour phenomenon. Various time varying loading conditions and scouring patterns were considered in the analysis. The results indicate a change in the structural behavior of substructure depending on the eroded area and pattern. The outcome of this research will be useful to suggest basic design guidelines for ground sills of the bridge substructure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.810-816
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• 2017

This study investigates the relationship between the damage patterns and structural performance levels of a multi-strand 7-wire strand that is used as an important member of stay cables. Stay cables are continuously damaged after completion, and corrosion is the main cause. However, it is difficult to check the damage pattern inside the cable due to its structural characteristics, and it is difficult to evaluate the degradation level of the damage quantitatively. This study derives the relationship between the damage pattern and the performance level of the stranded wire by comparing results and analyzing them through an indoor experiment and finite element analysis. In order to simulate the damage of a 7-wire strand, artificial damage was applied by mechanical precision machining to perform a performance evaluation. The results of the analysis show that regardless of the damage size of the strand, the structural performance deteriorated immediately after the damage. It was experimentally and analytically deduced that the type and amount of damage should be considered as a parameter for evaluating the performance level of the strand. This information can be used for the safety management of a cable stayed bridge by constructing a database according to the pattern and amount of damage.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2008.03a
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• pp.125-126
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• 2008

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.321-323
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• 1996

In this paper, it introduces a several circuit type of current-fed Full Bridge high frequence inverter with VVVF function. These inverter circuit presents various output control method according to on/off signal pattern of switches. also, It is certify that the accordance of characteristics is compared theoretical waveform with experimental results according to each signal pattern.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2011.09a
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• pp.3-21
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• 2011

Laboratory experiments and numerical simulations using Particle Flow Code (PFC2D) were performed to study the effects of joint separation and joint overlapping on the full failure behavior of rock bridges under direct shear loading. Through numerical direct shear tests, the failure process is visually observed and the failure patterns are achieved with reasonable conformity with the experimental results. The simulation results clearly showed that cracks developed during the test were predominantly tension cracks. It was deduced that the failure pattern was mostly influenced by both of the joint separation and joint overlapping while the shear strength is closely related to the failure pattern and its failure mechanism. The studies revealed that shear strength of rock bridges are increased with increasing in the joint separation. Also, it was observed that for a fixed cross sectional area of rock bridges, shear strength of overlapped joints are less than the shear strength of non-overlapped joints.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.787-792
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• 2002

The voided slab have many advantages, light weight, high load-distribution capacity, low cost and beautiful appearance, etc. But they have also many cracks due to difficulties in designs and construction, analysis, shrinkage, installation and rising force of voided tube. This paper presents the retrofit effects with steel plate(SP)/carbon fiber sheet(CFS) of RC voided slab. As a results of this study, it proved that the strip pattern has to be profitable than full-face pattern in performance such as crack, ultimate loads, stiffness. Retrofit length has many influence on retrofit effects, as the length increases, performance and stability of end blocks higher. Also, it proved that the retrofit on full-section has to be profitable than voided-section in performance, and the overlay length of CFS is desirable to extent approximately and welding(V-cut) has to be efficient than anchors in SP connection. But the kinds of end block and anchor has not influence on retrofit effects.

• Journal of the Korean Graphic Arts Communication Society
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• v.22 no.1
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• pp.83-94
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• 2004

PSR ink is used to insulation coating material that heat resistance is. The use purpose is used for bridge prevention, circuit protection, stabilization of insulation. Heat-cured resin was used mainly on the materials of PSR inks. But, UV-curing type resin in used. Also, because of recently environmental problem, ink is going to water type. Purpose of this study is to develop PSR ink that can develop in pure water. and experiment did that do from that find suitable oligomer and monomer and does brand ratio differ. Specially Knew that is extent water soluble UV resin develop possible is DPHA 10~50% that A/A1924 is 50~90wt %, monomer. As a result, when ratio of A/A1924 and DPHA low viscosity epoxy resin is 5:1.5:1.5, could get high sensibility pattern repeatability, tack and alkali-resistance.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.651-654
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• 2005

In this paper, an efficient switching pattern to equalize the size of transformer is proposed for a multi-level inverter employing cascaded transformers. It is based on the prior selected harmonic elimination PWM(SHEPWM) method. Because the maximum magnetic flux imposed on each transformer becomes exactly equal each to each, all transformers can be designed with the same size regardless of their position. Therefore, identical full-bridge inverter units can be utilized, thus improving modularity and manufacturability. The fundamental idea of the proposed switching pattern is illustrated and the analyzed theoretically. The validity of the proposed switching strategy is verified by experimental results.

• Proceedings of the KIEE Conference
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• summer
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• pp.1528-1530
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• 2004

In this paper, an efficient switching pattern to equalize the size of transformer is proposed for a multi-level inverter employing cascaded transformers. It is based on the prior selected harmonic elimination PWM(SHEPWM) method. Because the maximum magnetic flux imposed on each transformer becomes exactly equal each to each, all transformers can be designed with the same size regardless of their position. Therefore, identical full-bridge inverter units can be utilized, thus improving modularity and manufacturability. The fundamental idea of the proposed switching pattern is illustrated and then analyzed theoretically. The validity of the proposed switching strategy is verified by experimental results.

• Culinary science and hospitality research
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• v.2
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• pp.209-235
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• 1996

This study assesses consumer's eating-out pattern for Foodservice industry in Korea. Foodservice industry has become increasingly important because many businessman are looking it difficult to develop successful business as a consequence of the rapid growth in Foodservice industry in Korea This exploratory study originally nation-wide surveyed a 1450 consumer over the country. A research was conducted from July 1, to July 10, 1996 using as its subject domestic consumer over the country. The data obtained from the returned questionnaires was coded and transcribed for statistical analysis. The Statistical Package for social science program (SPSS) was used for computer analysis of the data. Findings indicated the problems of management structures, managerial techniques, and laggard counter measure against the korean government's open-door policy for dining-out industry. It is found that taste, F/B price, atmosphere are considered important in choice of restaurant. And korean consumer think it is that restaurant location, physical, evidence, quality of service, Ads of mouth and cleanliness. With the importance of dining-out industry to the business, economic, and social development of korea, it is imperative to bridge this gap for sustained growth and development. Moreover, this study for advancement and improvement through concrete and multi-directional data collection and in-depth analysis of consumer's eating-out pattern realities is required.