• Journal of Biomedical Engineering Research
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• v.31 no.6
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• pp.438-448
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• 2010

The social activities of the elderly have been increasing as our society progresses toward an aging society. As their activities are increased, the occurrence of falls that could lead to fractures are increased. Falls are serious health hazards to the elderly and we need more thorough understanding of falls including the progress of falls and the impact area in various fall directions. Many of the traditional methods of falls research dealt with voluntary falls by younger subject since older subject can easily get fracture from voluntary falls. So, it has been difficult to get exact data about falls of the elderly. Here, we tried to capture the characteristics of the movements of major joints using three dimensional motion capture system during falls experiments using a moving mattress that can safely induce unexpected falls. Healthy younger subjects participated in the actual falls experiment and the moving mattress was actuated by a pneumatic system. The kinematic parameters such as velocities of major segments were imported to a computer simulation environment and falls to hard surfaces were simulated in a computational environment using a realistic human model of aged persons. The simulation was able to give approximations to contact forces which can occur during actual falls. And we designed impact absorption system to reduce the impact during falls. We can adapt this system to fracture prevention system that we are going to study.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.145-149
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• 1980

Various methods have been so far proposed to find out the directions and spectra of sound waves from the sources for provisions of noise controls. The conventional methods are generally classified into three systems such as, single microphone system, moving microphone system and multi-microphone system, which composes a resultant super directivity by giving a appropriate delay and a weighting coefficient in the output of each microphone. In case of using a single microphone there is a difficulty in providing it with desirable super directivity in the low frequency range, while in case of using multi-microphone system there has been a disadvantage that the measurement of directivity could not separately be done with the spectrum analysing. And in case of the use of a moving microphone system it needs a condition that the sound source to be detected should be stationary state and in rest. However here we introduce a method that the spectral analysing and the directivity of synthesis can be separately carried out by using a linear array of many microphones, in which each output of the microphone is multiplied by appropriate weighting coefficient and all of those products are summed after passing through adequate filters. The resultant signal is then sampled with an adequate sampling frequency and taken average for processing.

• Journal of architectural history
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• v.6 no.3 s.13
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• pp.129-143
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• 1997

The perspective representation and its effect that appeared in the tombs and mural paintings of koguryo are summarized as follows: First, The inside structure of the tombs is likely to show the deepness effect, placing each function in the front and both sides centering around the mane pillars and creating the boundaries and the spaces that have various visibility between the inside and outside spaces of the structure just like a traditional Korean house shows. In addition, The deepness effect is emphasized by suggesting that the spaces are countinued with a storage attached behind the main house or by forming the level and deployment in a narrow space like the scene that a large array is looked out from the main house. Second, The deepness effect is expressed by making the form of ceiling turn to a vertical space of an ascending image, constructing it just as the lotus lamp ceiling of a wooden architecture or drawing it just like the imaginary heavenly world with the sun the moon and mythical fairies and animals spread in it. Thried, The perspective effect is disclosed by drawing the mural pictures in an equally set bird's-eye view without regard to the disfance proportion according to the conceptual visualization which is not a visual penetration, adopting the multiple view points and moving view points that are moving around as an important manner of seeing. Fourth, The deepness effect is emphasized through the scene of changing spaces when they are looked out far or looked into depending on a viewpoint of the daily life by forming the fromes of paintings that we made up with actual pillars, Du Gong, crossbeams or that are painted in most tombs. Fifth, The rich spatial senses are reflected by originating the characters of the three directions, level, deployment and ascending. An example which can support the conclusion of this study can be given here. that is, the construction ground plan of a dwelling house of a nobleman at the end of Koguryo as a remain which was excavated at Dongdae Ja in Jip An.

• Journal of Digital Convergence
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• v.15 no.5
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• pp.373-380
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• 2017

Recently, virtual reality contents are being experimented and introduced in various fields such as game, education, medical, exhibition, movie, SNS. However, research on virtual reality is mainly focused on industrial and technological perspectives, so contents-centric or contents-oriented research is on virtual reality is very rare. In order to prepare for the future of virtual reality properly, content-oriented research is very much needed. The purpose of this study is to investigate the types, characteristics, and possibilities of virtual reality contents applied to theme parks. For this purpose, we tried to classify the contents type of virtual reality based theme park. The criteria of type classification are divided into 'fixed type', 'continuous moving type', and 'segmented moving type' according to the player's position movement possibility and movement type, here we combine the senses such as tactile, taste, smell, balance etc.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.591-597
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• 1996

To straighten the path that farm machinery follows in paddy fields, it is necessary to measure and evaluate the tracks that these machines leave behind. However, there are no known methods for making such measurements and evaluations since it is difficult to accurately trace the paths that the machine make in paddy fields. Therefore, a measuring system has been developed which can accurately recored the path of a farm machinery in a field by measuring the horizontal straight-line distance from the side of the field to the machine. This system consists of a track subsystem on the machine and a range finder system. A measuring appraratus is installed on a flatcar which runs on rails over 50 m long at the side of the filed. The track subsystem uses a CCD camera to track the movement of the machine in the field which is following a lengthwise path. The range finder subsystem measures the distance that the measuring apparatus has traveled on the rails and the distance from the app ratus to the machine in the field. This system makes it possible to record the path that the machine travels. Even though differences in traveling distance arise between the measuring apparatus and the farm machine, these differences are detected by image processing , which allows the machine in the field to be located accurately. The short(0.05 second) time required for image processing is enough to follow an object . In the present study, this system was able to measure the path that a moving tractor makes. Even though a lag of up to 0.4 meters occurred, this system did not miss its target during operation of the track subsystem. Thus the path measuring system developed here is able to record vehicle paths automatically by following the movement of vehicles in the field and measuring the distance to them. It is expected to come into use in such applications as unmanned moving vehicle tests.

• Journal of the Korean association of regional geographers
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• v.11 no.4
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• pp.523-535
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• 2005

This study is aimed at researching the applicability of teaching-learning models in highschool geography class by designing the models on the basis of geographical experience the learners go through everyday life. The procedures and results of the application of the models are as followed. First, the systematization of the teaching concepts should be preceded to internalize the learners cognitive development, that is, to systemize cognitive structure. The concrete learning points of geographical concepts from the units about Migration and Population Changes are systemized with 'migration' as a higher concept, 'moving type' as basic concept, 'moving factors' as the lower concept. Everyday geographical experiences the students can go through are surveyed. Second, as preparation for the geography class, hand-outs about family-moving history and the change of the family number were used as basic material for real class teaching activity, showing the learners' general concepts are very effective as basic units which can be easily understood and accessed to. Third, with the experimental class, the geography class should secure the flexibility on the teaching-learning process. The result of applying the newly developed teaching-learning model to actual geography classes was that experimental group had higher achievement rate than the compared group with general teaching-learning model applied to. The result of analyzing students' response of the new teaching-learning model was that the students were interested and satisfied emphatically and they showed positive response in regard to practical use of the contents. Here, it is noticeable that the new teaching-learning model causes the students to be interested. But it's also found that there's no big difference in improving the students' inquisitive mind.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.1
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• pp.80-85
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• 2011

This paper presents the design of the power-assisted controller for the in-wheel type smart wheelchair by using torque estimation that is predicted by relationship between input voltage and output wheel angular velocity. Nowadays, interest of the moving assistant aids is increased according to the increase in population of the elderly and the handicapped person. However some of the moving assistant aids have problems. For example, manual wheelchair has difficulty moving at the slope, because users lack the muscular strength of their arm. In electric wheelchair case, users should be weak by being decreased muscles of upper body. To overcome these problems, power-assisted electric wheelchair are proposed. Most of the power-assisted electric wheelchair have the special rims that can measure the user's power. In here, the rims have to be designed to install the sensors to measure user's power. In this paper, we don't design the rim to measure the man power. To predict the man power, we propose a control algorithm of the in-wheeled electric wheelchair by using torque estimation from the wheel. First, we measure the wheel velocity and voltage at the in-wheel electric wheelchair. And then we extract driving will forces by using proposed mathematical model. Also they are applied at the controller as the control input, we verify to be able to control in-wheel type smart wheelchair by using simulation.

• Korean Journal of English Language and Linguistics
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• v.1 no.3
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• pp.349-368
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• 2001

We have brought up several distinct types of English clausal constructions, and have been lead to the descriptive generalization in (14),repeated here as (33): (33) Reduced clauses cannot occur in non-complement positions. The generalization in (33) refers to two theory-internal notions, reduced clauses and non-complement positions. Both notions are concerned with the composition of syntactic structures to be defined by X-bar theory. Without these theoretical notions, it would be difficult to describe in a general form the fact that certain types of complement clauses-namely, null-that clauses, if-clauses, Acc-ing gerund, ECM complement clauses, and Raising complement clauses-cannot occur in particular syntactic positions. Instead, one would have to describe this fact for each clause type, in such a way that null-that clauses cannot occur in such and such positions, and if-clauses cannot occur in such and such positions, and Acc-ing gerund cannot occur in such and such positions, and so on, although the positions in which they cannot occur are totally the same. Given the terminology of X-bar theory, however, it has turned out that these types of complement clauses are all reduced clauses, and the positions where they cannot occur are all non-complement positions. Then, the generalization has obtained that reduced clauses cannot occur in non-complement positions. It is a theoretical issue, and differs depending upon theories, how to explain why such a descriptive generalization holds at all. Hopefully, the demonstration here provides a piece of evidence showing that a theory or a particular theoretical nation plays an important role in the description of linguistic facts. Moreover, I have made a crucial prediction on the basis of the well-accepted theoretical assumption the ECM complement clauses and Raising complement clauses are reduced clauses; namely, the prediction that these types of clauses cannot occur in non-complement position. The prediction based upon the theoretical assumption is actually borne out, as illustrated earlier. The illustration of the prediction, I hope, shows that a theory or a particular theoretical assumption, coupled with another theoretical assumption, allows us to make some interesting predictions. Predictions serve to widen a range of linguistic facts to be described. A theory plays a crucial part in finding out interesting facts as well as in describing them in some general forms. Finally, let me state a few words as to the recent generative theory in connection with linguistic description. The recent generative theory is getting more and more abstract. I think it is moving toward a good direction as cognitive science. It will contribute, among others, to the inquiry into what is knowledge that is very specific to language faculty, and into how it interacts with other cognitive faculties. However, I am suspicious about how much the abstract generative theory will contribute to the description of linguistic facts in a particular language. While generative theory is claimed to aim both for descriptive adequacy and for explanatory adequacy, the recent generative theory is likely to put much more weight on explanatory adequacy. In my view, a less abstract theory is enough, or even more useful, for the purpose of linguistic description. Of course, how abstract theory one should adopt as a framework differs depending upon what aspect of language one attempts to describe. What I would like to emphasize here is that linguistic theory does not conflicts with linguistic description, and a linguistic theory with an appropriate degree of abstractness serves as a tool for finding out new interesting facts, as well as for describing them in some general, elegant forms.

• Management Science and Financial Engineering
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• v.14 no.2
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• pp.45-66
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• 2008

Refuse collection, one of important elements in reverse logistics, is an activity rendering recyclables or wastes and moving them to some points where further treatment is required. Among various decisions in the collection activity, we focus on network design, which is the problem of locating collection points as well as allocating refuses at demand points to collection points while satisfying the capacity restriction at each collection point. Here, the collection point is the place where recyclables or wastes near the point are gathered, and locating the collection points is done by selecting them from a given set of potential sites. The objective is to minimize the sum of fixed costs to open collection points and transportation costs to move refuses from demand points to collection points. An integer programming model is developed to represent the problem mathematically and due to the complexity of the problem, two types of heuristics, one with simultaneous and the others with separate location and allocation, are suggested. Computational experiments were done on test problems up to 500 potential sites, and the results are reported. In particular, some heuristics gave near optimal solutions for small-size test problems, i.e., 2% gaps in average from the optimal solution values.

• The Transactions of the Korea Information Processing Society
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• v.2 no.6
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• pp.831-838
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• 1995

Geometric transformations require many operations in displaying moving 3D objects on the screen and a fast computation is a important problem in CAD or animation applications. The general method to compute the transformation coordinates of an object represented by an octree must perform the operations on every node. This paper proposes an efficient method that computes the rectangular coordinates of the vertices of the octree nodes into the coordinates of the universe space using the basicvectors in order to compute quickly geometric transformations of 3D images represented by an octree. The coordinates of the vertices of each octant are computed by using the formula presented here, which requies additions and multiplications by powers of 2. This method has a very fast execution time and is compared with the general computation method.