• Structural Engineering and Mechanics
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• 제84권6호
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• pp.799-811
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• 2022

Adhesive bonding has seen rapid development in recent years, with emphasis to composite patch repairing processes of geometric defects in aeronautical structures. However, its use is still limited given its low resistance to climatic conditions and requirement of specialized labor to avoid fabrication induced defects, such as air bubbles, cracks, and cavities. This work aims to numerically analyze, by the finite element method, the failure behavior of a damaged plate, in the form of a bonding defect, and repaired by an adhesively bonded composite patch. The position and size of the defect were studied. The results of the numerical analysis clearly showed that the position of the defect in the adhesive layer has a large effect on the value of J-Integral. The reduction in the value of J-Integral is also related to the composite stacking sequence which, according to the mechanical properties of the ply, provides better load transfer from the plate to the repair piece through the adhesive. In addition, the increase in the applied load significantly affects the value of the J-Integral at the crack tip in the presence of a bonding defect, even for small dimensions, by reducing the load transfer.

• Imaging Science in Dentistry
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• 제50권2호
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• pp.141-151
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• 2020

Purpose: This study aimed to quantify the influence of tooth position within the field-of-view (FOV) on cone-beam computed tomography (CBCT) imaging artifacts' intensity when assessing teeth restored with various intracanal materials. Materials and Methods: Seventy single-rooted teeth were divided into 7 groups (10 teeth per group): NiCr post (NC), AgPd post (AP), metal core fiberglass post (MCFG), fiberglass post (FG), anatomical fiberglass post (AFG), fiberglass post cemented with core build-up cement (FGCo), and anatomical fiberglass post cemented with core build-up cement (AFGCo). All posts were cemented using a regular dual-curing resin cement (Allcem), except FGCo and AFGCo which were cemented with a core build-up dual-curing resin cement (AllcemCore). Each tooth was scanned on a CS9000 in 5 positions within the FOV: a central position, anterior horizontal peripheral, peripheral superior, peripheral inferior, and posterior horizontal peripheral position. Hyperdense, hypodense, remaining teeth areas and ROI areas were quantitatively analyzed using ImageJ software. Results: Posterior horizontal peripheral position increased the intensity of artifacts on FGCo and AFGCo post groups (P<0.05), and specifically the hypodense artifact intensity on FG and AFG post groups (P<0.05). NC and AP groups presented greater intensity of artifacts than any other post groups(P<0.05). Conclusion: Artifact intensity increases in the presence of high atomic number materials and when the object is not centered within the FOV. The impact of positioning within the FOV on artifact was greater for fiberglass posts cemented with core build-up dual-curing cement than for metal posts and fiberglass posts cemented with regular dual-curing cement.

• 환경영향평가
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• 제17권4호
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• pp.255-262
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• 2008

For the Han-river estuary and DMZ where white-naped crane (Grus vipio; endangered migratory bird) stopover or spend winter, the habitat composition and the habitat use pattern of white-naped crane were analyzed with the position data obtained by the satellite tracking method. By the use of geographic information system (GIS), the percent composition of seven habitat categories of white naped-crane data points (n=228) was analyzed. The chi-square test showed that the white-naped crane habitat use pattern was significantly different (p<0.05) from that of random points (n=228). It means that white-naped crane select and use particular habitat area in the Han-river estuary and DMZ.

• 기술혁신연구
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• 제6권1호
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• pp.187-214
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• 1998

This paper tries to examine the effectiveness of inventory reduction to the productivity increase and the impact of production environments on its effectiveness utilizing the Profit Impact of Market Strategy (PIMS) Database from the Strategic Planning Institute, a large data set that covers a variety of manufacturing activities from the early 1970s to late 1980s. The empirical results of this paper support the robustness of the principle of "Lean Production" or JIT system (also referred to as "Stockless Production"). We also find that the overall environment in which manufacturing strategic business units operate is an important factor in determining the different degrees of effectiveness of the work-in process (and raw materials) invertory reductions. In particular, we find that the effectiveness of the work-in process reduction varies according to the position in the product life cycly as well as the complexity and characteristics of the production processes.roduction processes.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.414-419
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• 1997

The free vibration analysis of cantilever CFRP and GFRP composite rectangular plates with point supports at the free edge and interior position is performed. The natural frequencies and mode shapes of plates are experimentally determined by impact testing using an impact hammer. To compare and verify these experimental results, the finite element analysis is also carried out and the non-dimensional frequency parameters are compared with FE analysis results. The effects of the number and location of the point support on the frequencies are examined. In the experimental results, it is found that a significant increase in frequencies occurs when the point supports are added on certain parts of plates.

• 한국정밀공학회지
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• 제14권4호
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• pp.126-135
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• 1997

A sensorless motion planner which succeeds in grasping a polygonal part firmly into a desired orientation has been developed through the dynamic analysis. The analytical results on the impact process with friction are used for modeling the contact motionduring the parallel-jaw grasp operation, which is com- posed of the pushing and the squeezing process. The developed planner succeeds in grasping a part into a specified orientation in the face of uncertainties of initial position and orientation of the part, motion direction of the finger, and the physical parameters such as the coefficients of friction and restitution. The motion planner has been fully implemented into a viable package on the computer system, and verified experimentally. The motion of parts is recorded using a high-speed video camera, and then compared to the results of the planner and the graphic simulation results that illustrate the simulated motion of the grasp operation.

• Structural Engineering and Mechanics
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• 제14권5호
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• pp.611-624
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• 2002

In this paper, a complete solution is presented for dynamic plastic response of a rigid, perfectly plastic hinged-free beam, of which one end is simply supported or hinged and the other end free, subjected to a transverse strike by a travelling mass at an arbitrary location along its span. The governing differential equations are expressed in non-dimensional forms and solved numerically to obtain the instantaneous deflection of the beam and the plastic dissipated energy in the beam. The dynamic behavior for a hinged-free beam is more complicated than that of a free-free beam. It transpires that the mass ratio and impact position have significant influence on the final deformation. In the aspect of energy dissipation, unlike simply supported or clamped beams for which the plastic deformation consumes almost the total input energy, a considerable portion of the input energy would be transferred as rigid-body motion of hinged-free beam, and the energy dissipated in its plastic deformation is greatly reduced.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1742-1745
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• 1997

We have developed a highly responsible probing system for inspection of electrical properties of assemble PCB$_{s}$ (printed circuit boards). However, as the duration of the impact occurring between a probe and a solder joint on PCB is very short, it is very difficult to control the harmful peak impact force and the slip motion of the probe to sufficient level only by its vorce feedback control with high gains. To overcome these disadvantages of the prototype, it needs ot obtain some information of the solder joint in advance before the contact. In addition, to guarantee the reliability of the probing task, the probing system is required to measure several points around the probale target point at high speed. There fore, to meet such requirements, we propose a new noncontaet sensor capable of detecting simultaneously position and normal vectors of the multiple points around the probable target point in real time. By using this information, we can prepare a control strategy for stable contact motion on impact. In this paper, we described measuring priniciple, design, and development of the sensor. The effectiveness of the proposed sensor is verified through a series of experiments.s.

• 동아시아경상학회지
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• 제4권3호
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• pp.1-17
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• 2016

Businesses are using culture marketing as a new promotional tool and as a marketing strategy since consumers have desire for not only economical fulfilment, but also emotional and psychological fulfilment. Similar to service industry, medical service industry has started to use culture marketing on its service industry management side. Therefore, this paper will propose necessity and usable culture marketing in hospitals to identify the current position of culture marketing in medical service industry. In conclusion, the present research offers the following implication. First, culture marketing has a partial offsetting impact to those who have negative emotion regarding the medical service industry. This is because of the positive impact of culture marketing on a customer response and customer satisfaction. Moreover, by considering the fact that only a culture synthesis and a culture style have a positive impact, focusing on a culture synthesis and a culture style would be treated as an advantageous strategy.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.36-37
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• 2015

Recently, there has been a rapid increase in demand for lightweight walls for their use as interior partitions, as types of structure have gradually changed from shear wall structures to column structures or flat plate column wall systems. The lack of resisting force in lightweight walls is found by measuring the depth of dents in impact resistance tests, but it is not a direct factor of impact resistance. However, in the user's position, dents of over a certain size are clearly a factor that visually reminds the need for repair. In this study, we reviewed relative methods of assessment of the need for repair based on the visual means of determination (sensory test) on the dents on lightweight walls. Dents were found to stand out starting from depths of about 4mm, and the depth of roughly 5mm was found to be the criterion for determining the necessity of repair for men, while it was 4mm for women.