• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.1016-1021
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• 1989

In this paper, we introduce a recursively-defined natural join operation as well as well-known object composition operations (union, intersection) for composing CAD database objects. Then, we will discuss how to realize these operations by the message passing computing mechanism. Next, we will discuss what kind of behaviours (methods) are preserved under our natural join operations. Finally, we investigate mathematical properties about the relationships among several object composition operations (natural join, union and intersection).

• Journal for History of Mathematics
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• v.1 no.1
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• pp.14-32
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• 1984

The concepts of zero, minus, infinite, ideal point, etc. are not real existence, but are pure mathematical objects. These entities become mathematical objects through the process of a philosophical filtering. In this paper, the writer explores the relation between natural conditions of different cultures and philosophies, with its reference to fundamental philosophies and traditional mathematical patterns in major cultural zones. The main items treated in this paper are as follows: 1. Greek ontology and Euclidean geometry. 2. Chinese agnosticism and the concept of minus in the equations. 3. Transcendence in Hebrews and the concept of infinite in modern analysis. 4. The empty and zero in India.

• Journal of Haehwa Medicine
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• v.23 no.2
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• pp.1-4
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• 2015

Learning can be defined as its objects, main question for the objects, and its unique way to organize all the knowledge acquired as the results of the question. From the point of view like this, Traditional Korean Medicine(TKM) can be defined as learning for human body and its functions, health and diseases based on the theory of the Yin and Yang and of the five elements. Nowaday Many papers based on laboratory work publish for the name of scientization of TKM, but from the viewpoint of definition of learning, they have a problem that there is no basic theory. If TKM could be communicated with western natural science, it has to be solved. And oriental physiology has a same object and same questions with western physiology, so oriental physiology can be useful to make a bridge between TKM and western natural science.

• Journal of the Korea Furniture Society
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• v.26 no.1
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• pp.92-99
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• 2015

The following research focused on developing a new concept of lighting design with design factors which considered combining common natural objects with feelings. The purpose of this research is to write a thesis that deals with the whole process of developing a design for 'FEELighting' that is applicable to daily life through developing a form of lighting, which prioritizes feelings rather than materials, forms, or functions, and enhance the quality of people's lives. In particular, the process has been materialized by defining a new concept of 'FEELighting' (Feeling + Lighting), researching and analyzing the original and unfamiliar correlation between feeling and lighting, and choosing the embedded acrylics lighting items that can undergo small quantity batch production. As a result, prototypes of various forms of lightings that could be applied to daily lives -ceiling lights, wall light lamps, and table lamps-, which were made by combining numerous common natural objects and surpassed simple function and created to surpass simple lighting function, were presented through every process of design development.

• Journal of Computational Design and Engineering
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• v.1 no.4
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• pp.289-297
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• 2014

Although big-sized markers are good for accurate marker recognition and tracking, they are easily occluded by other objects and deteriorate natural visualization and level of immersion during user interaction in AR environments. In this paper, we propose an approach to exploiting the use of rectangular markers to support tangible AR interaction based on fingertip touch using small-sized markers. It basically adjusts the length, width, and interior area of rectangular markers to make them more suitably fit to longish objects like fingers. It also utilizes convex polygons to resolve the partial occlusion of a marker and properly enlarges the pattern area of a marker while adjusting its size without deteriorating the quality of marker detection. We obtained encouraging results from users that the approach can provide better natural visualization and higher level of immersion, and be accurate and tangible enough to support a pseudo feeling of touching virtual products with human hands or fingertips during design evaluation of digital handheld products.

• The Transactions of the Korea Information Processing Society
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• v.7 no.4
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• pp.1082-1091
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• 2000

In Distributed Shared Memory systems, false sharing occurs when two different data items, not shared but accessed by two different processors, are allocated to a single block and is an important factor in degrading system performance. The paper first analyzes shared memory allocation and reference patterns in parallel applications that allocate memory for shared data objects using a dynamic memory allocator. The shared objects are sequentially allocated and generally show different reference patterns. If the objects with the same size are requested successively as many times as the number of processors, each object is referenced by only a particular processor. If the objects with the same size are requested successively much more than the number of processors, two or more successive objects are referenced by only particular processors. On the basis of these analyses, we propose a memory allocation scheme which allocates each object requested by different processors to different pages and evaluate the existing memory allocation techniques for reducing false sharing faults. Our allocation scheme reduces a considerable amount of false sharing faults for some applications with a little additional memory space.

• Journal of Communications and Networks
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• v.8 no.3
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• pp.330-338
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• 2006

Many web cache systems and policies concerning them have been proposed. These studies, however, consider large objects less useful than small objects in terms of performance, and evict them as soon as possible. Even if this approach increases the hit rate, the byte hit rate decreases and the connections occurring over congested links to outside networks waste more bandwidth in obtaining large objects. This paper puts forth a client-cluster approach for improving the web cache system. The client-cluster is composed of the residual resources of clients and utilizes them as exclusive storage for large objects. This proposed system achieves not only a high hit rate but also a high byte hit rate, while reducing outgoing traffic. The distributed hash table (DHT) based peer-to-peer lookup protocol is utilized to manage the client-cluster. With the natural characteristics of this protocol, the proposed system with the client-cluster is self-organizing, fault-tolerant, well-balanced, and scalable. Additionally, the large objects are managed with an index based allocation method, which balances the loads of all clients well. The performance of the cache system is examined via a trace driven simulation and an effective enhancement of the proxy cache performance is demonstrated.

• Journal of Astronomy and Space Sciences
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• v.32 no.4
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• pp.411-417
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• 2015

Several optical monitoring strategies by a ground-based telescope to protect a Geostationary Earth Orbit (GEO) satellite from collisions with close approaching objects were investigated. Geostationary Transfer Orbit (GTO) objects, Inclined GeoSynchronous Orbit (IGSO) objects, and drifted GEO objects forced by natural perturbations are hazardous to operational GEO satellites regarding issues related to close approaches. The status of these objects was analyzed on the basis of their orbital characteristics in Two-Line Element (TLE) data from the Joint Space Operation Center (JSpOC). We confirmed the conjunction probability with all catalogued objects for the domestic operational GEO satellite, Communication, Ocean and Meteorological Satellite (COMS) using the Conjunction Analysis Tools by Analytical Graphics, Inc (AGI). The longitudinal drift rates of GeoSynchronous Orbit (GSO) objects were calculated, with an analytic method and they were confirmed using the Systems Tool Kit by AGI. The required monitoring area was determined from the expected drift duration and inclination of the simulated target. The optical monitoring strategy for the target area was analyzed through the orbit determination accuracy. For this purpose, the close approach of Russian satellite Raduga 1-7 to Korean COMS in 2011 was selected.

• Journal of Sensor Science and Technology
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• v.24 no.3
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• pp.169-174
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• 2015

In this study, we developed a system to detect the various defects in the metallic objects using the phenomenon that the defects cause the changes of the natural resonant frequencies. Our system consists of a FFT Amp, an Auto Impact Hammer, a Hammer controller and a PC. Auto Impact Hammer creates vibrations in the metallic objects when tapped on the surface. These vibrational signals are converted to the voltage signals by an acceleration sensor attached to the metallic part surface. These analog voltage signals were fed into an ADC (analog-digital converter) and an FFT (fast fourier transform) conversion in the FFT Amp to obtain the digital data in the frequency domain. Labview graphical program was used to process the digital data from th FFT amp to display the spectrum. We compared those spectra with the standard spectrum to find the shifts in the resonant frequencies of the metal parts, and thus detecting the defects. We used PCB's acceleration sensor and TI's TMS320F28335 DSP (digital signal processor) to obtain the resolution of 2.93 Hz and to analyze the frequencies up to 44 kHz.

• Journal of Information Processing Systems
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• v.12 no.4
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• pp.612-630
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• 2016

As mobile augmented reality technologies are spreading these days, many users want to produce augmented reality (AR) contents what they need by themselves. To keep pace with such needs, we have developed a mobile AR contents builder (hereafter referred to as MARB) that enables the user to easily connect a natural marker and a virtual object with various interaction events that are used to manipulate the virtual object in a mobile environment so that users can simply produce an AR content using natural photos and virtual objects that they select. MARB consists of five major modules-target manger, virtual object manager, AR accessory manager, AR content manager, and AR viewer. The target manager, virtual object manager and AR accessory manager register and manage natural target markers, various virtual objects and content accessories (such as various decorating images), respectively. The AR content manger defines a connection between a target and a virtual object with enabling various interactions for the desired functions such as translation/rotation/scaling of the virtual object, playing of a music, etc. AR viewer augments various virtual objects (such as 2D images, 3D models and video clips) on the pertinent target. MARB has been developed in a mobile application (app) format in order to create AR contents simply using mobile smart devices without switching to a PC environment for authoring the content. In this paper, we present the detail organizations and applications of MARB. It is expected that MARB will enable ordinary users to produce diverse mobile AR contents for various purposes with ease and contribute to expanding the mobile AR market based on spread of a variety of AR contents.