• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.05a
• /
• pp.644-647
• /
• 2005

In this paper, computer simulations with the absolute nodal coordinate formulation for large deformation problems in flexible multibody dynamics are compared to the real experiments. A high speed camera was employed to capture the deformed shapes of a thin beam, a plate, a rotating chain, and a paper strip. The measured data was used to calculate precise values for stiffness and damping ratio of the objects. Also a rotating strip and a helicoseir problem were formulated for computer simulation, and the computational results are also compared to the experiments.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.177-180
• /
• 2002

Generally, it is very difficult to inspect geometric shape of large 2D objects after machining. To maintain the accuracy for inspection, a robot vision is used to divide overall shape into several enlarged images, and image processing technique is applied to acquire one minute geometric contour. The inspection is to compare the NC data with the measured contour data by the vision system, and the algorithm is to rotate to minimize the maximum deviation coinciding two geometric centers. This paper experimentally shows that the proposed inspection algorithm is very useful fur a large machined object.

• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.1505-1510
• /
• 2007

Recently, efficient manufacturing of high precision is an important issue in modern industry as more variety of industrial products is being designed with compound surfaces. Rapid CAD data generation can be possible based on a non-contact type CMM of object through the use of reverse engineering. However, some registration to match the data measured from various directions into a common coordinate system is required. Also, the error can happen if it uses the conventional method to large product of thin thickness. So it is necessary to develop a new method, which was designed for the registration of large and thin products. Additionally, an algorithm to pick up coordinates for the newly designed method was proposed.

• Journal of the Optical Society of Korea
• /
• v.5 no.3
• /
• pp.70-75
• /
• 2001

Next Generation Space Telescope (NGST) is under design study for proposed launch around 2008. It will take over the task of Hubble Space Telescope (HST) and provide much more detailed information about celestial objects. Present large telescopes both in space and on the ground contain aspheric mirrors, called Ritchey-Chretien type. As the size of the telescope becomes larger and the optical quality is requested to be higher, reaching the diffraction limit, more accurate optical testing methods are required. However, there are few testing methods which can achieve the required accuracy for aspheric optics, and none of them has achieved it with certainty. The failure of producing the primary mirror of the Hubble Space Telescope to meet specification is a good example. Moreover, testing aspheric mirrors of large convex form adds the difficulty to extreme. In this paper, space telescopes and large ground-based telescopes are surveyed and testing methods for aspheric optics are reviewed. a method of testing aspheric convex mirrors is suggested.

• The Bulletin of The Korean Astronomical Society
• /
• v.44 no.1
• /
• pp.62.1-62.1
• /
• 2019

Current large observational projects perform both static and dynamic sky surveys. The Thirty-Minute Target of Opportunity (TMT) is the project focusing on the dynamic sky survey using Korea Microlensing Telescope Network (KMTNet) that is the best observing system to investigate the dynamic sky. TMT aims to perform and experiment on following components : 1) to select transient or variable sources having hour to day scale cadences for future science cases, 2) to optimize the observation strategy for these objects, 3) to provide automated photometric pipelines for the time series data, and 4) to test the data release environment for all astronomers. In the near future, it is expected that a huge number of events will be alerted through large area surveys such as LSST. Therefore, the TMT project will provide opportunities to prepare the future large survey era as well as to understand the nature of interesting astronomical events.

• Journal of Korean Physical Therapy Science
• /
• v.3 no.4
• /
• pp.159-169
• /
• 1996

Every citizen has a right to get the least health care service for their living and should be guaranteed the right of health which is specified in the constitution of Korea. Therefore, health care service should realize the equity and accessibility of service by the equitable distribution which is needed for health care. The objects of this study were the patients who was treated by the physical therapy in health care center(two of them located in cities and others are in agricultural areas). These are the results of our study. First, the age, job, sex and experience of former treatment of objects showed no meaningful statistic difference in the part of convenience of health care center, where as the system of health scurity showed highly meaningful difference. Second, The age, job and system of health care of objects showed no meaningful difference in the part of attitude and appreciation to therapist, where as the experience of former treatment in other center showed highly meaningful difference. Third, The age, job and sex of objects showed no meaningful difference in the part of the appreciation to results of service, where as the system of health scurity and the experience of former treatment in other center showed meaningful difference. To offer the effective physical therapy, the government of province or nation should invest the large amount of financial fund continuously and make the plan of efficient operating system for the physical therapy service room of public health center which is the most nearly located to native citizen. The problem of distance, low reliability to public service, public relation and reliabity should be improved to raise the utility of physical therapy room. And also, the physical therapy room should be opened in health subcenter to offer the condition of the native citizen's healthy life.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.19 no.10
• /
• pp.1910-1924
• /
• 1994

Curved 3D objects represented by range data contain large amounts of information compared with planar objects, but do not have distinct features for matching to those of object models. This makes it difficult to represent and identify a general 3D curved object. This paper introduces a new view-point independent approach to recognizing general 3D curved objects using range data. Our approach makes use of the relative geometric differences between particular points on the object surface and some model points. The model points are prespecified arbitrarily and keeping the task in mind so that the following task can be easily described using the model points. Our approach has several advantages. Since model points are specified arbitrarily and task dependently, further processing can be reduced in application by locating the model points at places which are useful for further operations in the task. The knowledge base is simple with less storage requirement. And, it is easy to compensate the uncertainties of positions estimation caused by noise and quantization error.

• Journal of the Korea Computer Graphics Society
• /
• v.5 no.1
• /
• pp.27-33
• /
• 1999

In this paper, we propose an efficient technique for the animation of flexible thin objects. Mass-spring model was employed to represent the flexible objects. Till now, many techniques have used the mass-spring model to generate plausible animation of soft objects. A straight-forward approach to the animation with mass-spring model is explicit Euler method, but the explicit Euler method has serious disadvantage that it suffers from 'instability problem'. The implicit integration method is a possible solution to overcome the instability problem. However, the most critical flaw of the implicit method is that it involves a large linear system. This paper presents a fast animation technique for mass-spring model with approximated implicit method. The proposed technique stably updates the state of n mass-points in O(n) time when the number of total springs are O(n). We also consider the interaction of the flexible object and air in order to generate plausible results.

• Journal of KIISE
• /
• v.42 no.3
• /
• pp.390-398
• /
• 2015

Spatial web objects refer to web documents that contain geographic information. Recently, services that create spatial web objects have increased greatly because of the advancements in devices such as smartphones. For services such as Twitter or Facebook, simple texts posted by users is stored along with information about the post's location. To search for such spatial web objects, a method that uses spatial information and text information simultaneously is required. Conventional spatial web object search methods mostly use R-tree and inverted file methods. However, these methods have a disadvantage of requiring a large volume of space when building indices. Furthermore, such methods are efficient for searching with many keywords but are inefficient for searching with a few keywords.. In this paper, we propose a spatial web object search method that uses a quad-tree and a patricia-trie. We show that the proposed technique is more effective than existing ones in searching with a small number of keywords. Furthermore, we show through an experiment that the space required by the proposed technique is much smaller than that required by existing ones.

• Proceedings of the KSRS Conference
• /
• v.1
• /
• pp.106-109
• /
• 2006

Over the years, many researches have been performed to create 3D digital maps. Nevertheless, it is still time-consuming and involves a high cost because a large part of 3D digital mapping is conducted manually. To compensate this limitation, we propose methodologies to represent 3D objects as 3D symbols and locate these symbols into a base map automatically. First of all, we constructed the 3D symbol library to represent 3D objects as 3D symbols. In the 3D symbol library, the attribute and geometry information are stored, which defines factors related to the types of symbols and related to the shapes respectively. These factors were used to match 3D objects and 3D symbols. For automatic mapping of 3D symbols into a base map, we used predefined parameters such as the size, the height, the rotation angle and the center of gravity of 3D objects which are extracted from Light Detection and Ranging (LIDAR) data and 2D digital maps. Finally, the 3D map in urban area was constructed and the mapping results were tested using aerial photos as reference data. Through this research, we can identify that the developed the algorithms can be used as effective techniques for 3D digital cartographic techniques