• Structural Engineering and Mechanics
• /
• v.70 no.6
• /
• pp.711-722
• /
• 2019

Considering stress singularities at point support locations, buckling solutions for plates with arbitrary number of point supports are hard to obtain. Thus, new Hp-Cloud shape functions with Kronecker delta property (HPCK) were developed in the present paper to examine elastic buckling of point-supported thin plates in various shapes. Having the Kronecker delta property, this specific Hp-Cloud shape functions were constructed through selecting particular quantities for influence radii of nodal points as well as proposing appropriate enrichment functions. Since the given quantities for influence radii of nodal points could bring about poor quality of interpolation for plates with sharp corners, the radii were increased and the method of Lagrange multiplier was used for the purpose of applying boundary conditions. To demonstrate the capability of the new Hp-Cloud shape functions in the domain of analyzing plates in different geometry shapes, various test cases were correspondingly investigated and the obtained findings were compared with those available in the related literature. Such results concerning these new Hp-Cloud shape functions revealed a significant consistency with those reported by other researchers.

• The korean journal of orthodontics
• /
• v.51 no.4
• /
• pp.260-269
• /
• 2021

Objective: To identify the most favorable sites that optimize the initial stability and survival rate of orthodontic mini-implants, this study measured hard and soft tissue thicknesses in the median and paramedian regions of the palate using cone-beam computed tomography (CBCT) and determined possible sex- and age-related differences in these thicknesses. Methods: The study sample comprised CBCT images of 189 healthy subjects. The sample was divided into four groups according to age. A grid area was set for the measurement of hard and soft tissue thicknesses in the palate. Vertical lines were marked at intervals of 0, 1.5, and 3.0 mm lateral to the midpalatal suture, while horizontal lines were marked at 2-mm intervals up to 24 mm from the posterior margin of the incisive foramen. Measurements were made at 65 points of intersection between the horizontal and vertical lines. Results: The palatal hard tissue thickness decreased from the anterior to the posterior region, with a decrease in the medial-to-lateral direction in the middle and posterior regions. While the soft tissue was rather thick around the lateral aspects of the palatal arch, it formed a constant layer that was only 1-2-mm thick throughout the palate. Statistically significant differences were observed according to sex and age. Conclusions: The anterolateral palate as well as the midpalatal suture seem to be the most favorable sites for insertion of orthodontic mini-implants. The thickness of the palate differed by age and sex; these differences should be considered while planning the placement of orthodontic mini-implants.

• Journal of the Korea Society of Computer and Information
• /
• v.12 no.6
• /
• pp.11-20
• /
• 2007

Even though much research has been performed to recommend favorite items to the buyers in the internet shopping mall, to the best of our knowledge. it is hard to find previous research on the recommendation of buy points. In this paper, we propose a method which can be used to recommend buy points of an item to the buyers. To do this, a database containing normalized price patterns is constructed from the archive of past prices. Then, the future price pattern is retrieved from the database based on the similarity. Here, regression analysis is used to find and analyze the elements that affect the price. We also present performance results showing that the proposed method can be useful for shopping malls.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2006.05a
• /
• pp.17-24
• /
• 2006

We consider the sensor location problem (SLP) on a given sensor field. We present the sensor field as grid of points. There are several types of sensors which have different detection ranges and costs. If a sensor is placed in some point, the points inside of its detection range can be covered. The coverage ratio decreases with distance. The problem we consider in this thesis is called multiple-type differential coverage sensor location problem (MDSLP). MDSLP is more realistic than SLP. The coverage quantities of points are different with their distance form sensor location in MDSLP. The objective of MDSLP is to minimize total sensor costs while covering every sensor field. This problem is known as NP-hard. We propose a new integer programming formulation of the problem. In comparison with the previous models, the new model has a smaller number of constraints and variables. This problem has symmetric structure in its solutions. This group is used for pruning in the branch-and-bound tree. We solved this problem by branch-and-cut(B&C) approach. We tested our algorithm on about 60 instances with varying sizes.

• Journal of Software Assessment and Valuation
• /
• v.17 no.2
• /
• pp.151-159
• /
• 2021

To derive grid lines for analyzing a table layout, line image enhancement techniques are studying such as various filtering or morphology methods. In spite of line image enhancement, it is still hard to extract line components and to express table cell's layout logically in which the cutting points are exist on the line or the tables are skewing . In this paper, we proposed a line tracking algorithm to extract line components under the cutting points on the line or the skewing lines. The table document layout analysis algorithm is prepared by searching grid-lines, line crossing points and gird-cell using line tracking algorithm. Simulation results show that the proposed method derive 96.4% table document analysis result with average 0.41sec processing times.

• Journal of the Korea Society of Computer and Information
• /
• v.20 no.4
• /
• pp.87-93
• /
• 2015

Recently, an idea has been suggested in which members construct the network by sharing their surplus bandwidth of their own access point. This kind of network is called public-shared network. As an application, SVC video streaming delivery system on public-shared network has been proposed. To send video stream from the stream server to clients, a tree structure is constructed where the root is a stream server, internal nodes are sharable access points, and leafs are clients. The previous researches have focused on constructing the minimal sharable-bandwidth tree which can serve all video streaming requests using the minimal sharable bandwidth. In this paper, we have shown that the problem of constructing a tree structure with given sharable access points to serve maximal video streaming requests is NP-hard. We also have developed an efficient heuristic algorithm for this problem and evaluated experimentally our algorithm.

• The Bulletin of The Korean Astronomical Society
• /
• v.36 no.2
• /
• pp.155.1-155.1
• /
• 2011

The Korea Astronomy and Space Science Institute (KASI) and the Department of Astronomy at the University of Texas at Austin (UT) are developing a near infrared wide-band high resolution spectrograph, IGRINS (Immersion Grating Infrared Spectrograph). The white-pupil design of the instrument optics uses 7 cryogenic mirrors including 3 aspherical off-axis collimators and 4 flat fold mirrors. Two of the 3 collimators are H- and K-band pupil transfer mirrors and they are designed as compensators for the system alignment in each channel. Therefore, their mount design will be one of the most sensitive parts in the IGRINS optomechanical system. The other flat fold mirrors are designed within the limited area. Each of those includes the features of 3 axial hard points and 2 radial hard points with one spring plunger in order for the proper deflection of the mirror. The design work will include the computer-aided 3D modeling and finite element analysis (FEA) to optimize the structural stability and the thermal behavior of the mount models. The mount body will also include a tip-tilt and translation adjustment mechanism to be used as the alignment compensators.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.14 no.3
• /
• pp.217-227
• /
• 1992

The purpose of this paper is to investigate changes in soft tissue in 22 patients treated by vertical ramus osteotomy and sagittal split ramus osteotomy for the correction of mandibular prognathism. 22 individuals, 12 males and 10 females, were selected from the patients with mandibular prognathism at the Department of Oral and Maxillofacial Surgery, Colledge of Dentistry, Kyung Hee University. Patient were analyzed with cephalogram taken 1 week before and at least 6 weeks after surgery under the same condition. Measurements were made constructed hard tissue and sop tissue points located on each before-and-after film tracing. Comparision were made of these figures to estimate the amount that the soft tissue followed the hard tissue structures in each surgical procedure : ratio of sop and hard tissue changes were formulated. The results were as follows. 1. The horizontal changes of Pogs and Bs as a ratio of the horizontal changes of Pog and B point were 1.02 and 1.16 respectively. 2. One millimeter of posterior changes at Pog resulted in 0.86mm of posterior change at Li and 0.09mm of posterior change at Ls. The greatest amount of sop tissue change occurred at Pogs, with substantially less posterior displacement at Bs, even less at Li and at least at Ls. 3. The ratio of LI to Li was 1:0.81 and the ratio of LI to Ls was not significant.(1 : 0.17) 4. The ULA(Cm-Sn-Ls) and the relative lower lip projection (LLP) was incnease4 but the relative upper lip projection (ULP) was slightly decreased 5. The angular change of the upper lip inclined angle (Ls-Sn/ANS-PNS) and lower lip inclined angle(Li-Pogs/Me-Go) expressed as a ratio of the posterior change of Pog were 0.57 and 0.20 respectively. 6. The ratio of the lower anterior facial height change of the soft tissue(Sn-Mes) to the hard tissue(ANS-Gn) were 0.78 and and the ratio of vertical height changes of the hard tissue and sop tissue to the posterior change of the Pog were 0.18 and 0.19 respectively. 7. The sop tissue angular change of facial convexity(G-Sn-Pogs) expressed as a ratio of the angular change of the hard tissue angle of facial convexity(N-A-Pog) was 1.24.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.14 no.2
• /
• pp.1-8
• /
• 2006

In this paper, an optimum design technology is developed to find an optimal position of the shock absorber using ADAMS and VisualDOC. A vehicle with a torsion-beam rear suspension is modeled by using ADAMS. Design variables for the optimal positioning of the shock absorber are defined considering the hard points of the chassis structure and design positioning are specified through the sensitivity analysis using a bump-crossing simulation. The objective function is defined as the joint reaction forces of the shock absorber connecting joints of the chassis structure. Sequential Quadratic Programming and Genetic Algorithms are used for this study. To validate the optimized design variables, pothole simulations are performed. GA showed better results than SQP algorithms for this design purpose.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.16 no.5
• /
• pp.385-389
• /
• 2003

There are four main components of the CMP process: polishing pad, slurry, elastic supporter, and pad conditioner. The polishing pad is an essential component to the reproducibility of polishing uniformity in CMP process. However, the polishing pad in recently using metal CMP raised the several points of high cost caused by the increase of cycle time and the many usage of slurry. It is necessary to develop the novel polishing pad which would lead the cost reduction by the higher pad life-cycle, minimized cycle time and lower slurry usage. The characteristics of polishing pad were studied on the effects of different sets of the Polishing pad, which can be applied to metal chemical mechanical polishing process for global planarization of multilevel interconnection structure. The main purpose of this experiment is cost reduction by the increase of pad life-time, the decrease of cycle time and the lower usage of slurry through the specific hard porous structured pad design. It is confirmed that the novel polishing pad made the slurry usage decrease to 60% as well as the pad life-time increase twice with the 25% improvement of removal rate. The polishing time could be decreased and it also helped the cycle time to diminish. It can be expected that this results will help both the process throughput and the device yield to be improved.