• Journal of the Korean Society for Precision Engineering
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• v.19 no.8
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• pp.161-171
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• 2002

This paper presents a linear motor, which generates large thrust with a low operating rate. In industrial fields there is a need for actuators that work with a low duty cycle but generate large thrusts. An example of such a case is provided by the actuators for ejector mechanisms in electric injection molding machines. The ordinary LSM (linear synchronous motor) is unsuitable for this large-thrust and low-operating-rate usage, because of its large size and high cost. This paper contains experimental results on linear motors that can generate large thrusts for a short time, and which can be cheaply produced. The described linear motor could be contained space of $250mm \times250mm\times 250mm$ and generate a maximum thrust of about 20000 N at a current of 250 A.

• Journal of the Korea Furniture Society
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• v.24 no.1
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• pp.88-103
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• 2013

Households of today tend to gradually change from a large household to a small one. The tendency starts from urban concentration of population with modern industrial society. Small-sized households have rapidly increased with the following three reasons: (i) one-person households with aging society, (ii) individualistic pursuit of happiness, and (iii) emergence of single households due to high prices and a decline in the quality of life. With these social changes, various products for small-sized households have been created and there have also been changes in dwelling patterns with small-size housing and one rooms increasing. Current small-sized living space has combined space of a living room, a bedroom and a kitchen, which makes a house compositive space. A bathroom, however, requires a differentiated suggestion from existing one since it is special space where water is used. Based on this issue, this study intends to present bathrooms in small-sized living space.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.495-499
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• 2006

While the use of large scale underground complex space is increasing currently, this research suggests the methodology of servicing advanced service for civilian and constructing active disaster protection system in order to be free from danger problem of underground complex space by applying new ubiquitous technology. Synchronization between virtual space and real space and construction of ubiquitous disaster protection system arc the core technology. Based on RFID, USN technology, usually, user centered spatial information services are presented. it can be convert to disaster protection system on emergency situation without delay. Through these technology. we can ensure the safety of underground space where the floating population is concentrated in, moreover, utilize for infrastructure that presents various civilian services. Then we can satisfy the increasing civilians desire for safety and welfare and finally, it will contribute to construction of productive city and creation of new conceptual market.

• Journal of Biosystems Engineering
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• v.24 no.4
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• pp.335-342
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• 1999

Air and flue gas temperature distributions in the space heater for greenhouse were measured to develop a thermal design technology for the space heater. Also, the characteristics of the fan supplying air to the space heater were investigated. The temperature of the flue gas inside the flue gas tube was linearly decreased as the lenght of than those of the flue gas with the oxygen concentration of 8.25% at the last exit of the second flue gas tube. Thus, the operating efficiency of the space heater could be increased with low air ratio decreased exhausting gas temperature and saved the energy consumption with decreased excess air flow. The temperature of the air supplied by fan was increased slowly around the first flue gas tube, meanwhile, increased sharply around the second flue gas tube due to large LMTD (Logarithmic Mean Temperature Difference) at the first flue gas tube than which of the second flue gas tube.

• Journal of the Korean Ceramic Society
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• v.36 no.9
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• pp.923-929
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• 1999

The cause of optical nonlinearity induced in thermally poled silica glass is believed to be the space charge polarization. Since the second order optical nonlinearity (electro-optic effect) can be used in optical switches the optical nonlinearity in silica glass has drawn a large attention. Space charge polarization occurs when an ionic conducting material is subjected to dc electric field by the blocking electrode. Thermal poling performed to induce the optical nonlinearity in silica glass is basically identical to the process generating space charge polarization. As a first step to understand the mechanism of space charge polarization in silica glass hence the induced optical nonlinearity the absorption currents as functions of time were measured for various types of silica glasses and analyzed by the theory of space charge polarization. It was found that the electrical relaxation exhibited a step by the space charge polarization in the relatively long time range and dielectric loss peak showed a maximum at a specific temperature which is depending on type of silica glass. It was turned out that this relaxation might be a cause of nonlinearity in electrical conductivity of silica glass.

• Korean Institute of Interior Design Journal
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• v.24 no.2
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• pp.108-116
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• 2015

The probability of visual perception occurrence varies in case the expectation of using each unit space of which the whole space consists because the size of space subject to analysis is very large or the organization is complicated in the analysis of spatial visual configuration. Therefore, it is necessary to compensate space analysis and index measurement by applying weight to the point of view for the probability of experiencing space. This study proposed a method of analyzing visibility ratio by applying the integration of space syntax theory as weight, and grasped the effect in comparison with the visibility ratio when weight was not applied.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.76.2-76.2
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• 2014

코로나그래프는 우주환경의 변화의 주요원인인 코로나물질방출을 관측할 수 있는 핵심우주관측기이다. 지난 약 18여년간 운용되어 왔던 SOHO 위성의 LASCO (Large Angle and Spectrometric Coronagraph) 탑재체의 노후화로 인한 운용 종료를 앞두고 있어 새로운 코로나그래프의 개발이 시급하다. 본 연구에서는 우주환경예보의 활용과 태양코로나와 코로나물질 방출에 관한 새로운 과학적 발견을 위해 적합한 위성용 코로나그래프의 개발방향을 제안하고 국제우주정거장이나 우리나라 위성을 활용하여 개발하는 경우에 극복해야 할 현실적인 기술 한계와 극복 방안에 대해 토의한다.

• The KIPS Transactions:PartA
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• v.13A no.2 s.99
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• pp.95-100
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• 2006

I design an Embedded File System in Linux Operating System by applying modified LZSS compressed algorithm. This suggested Compressed File System which is modified file system of the Linux O.S saves the storage space. The compressed file system supports efficient use of storage space. The suggesting file system solves the small space of embedded system. The suggesting file system of this paper gives effect of the large storage space without extending the storage space.

• Communications of the Korean Mathematical Society
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• v.37 no.1
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• pp.17-29
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• 2022

A commutative ring with unity R is called an EM-ring if for any finitely generated ideal I there exist a in R and a finitely generated ideal J with Ann(J) = 0 and I = aJ. In this article it is proved that C(X) is an EM-ring if and only if for each U ∈ Coz (X), and each g ∈ C^* (U) there is V ∈ Coz (X) such that U ⊆ V, ${\bar{V}}=X$, and g is continuously extendable on V. Such a space is called an EM-space. It is shown that EM-spaces include a large class of spaces as F-spaces and cozero complemented spaces. It is proved among other results that X is an EM-space if and only if the Stone-Čech compactification of X is.

• Electronics and Telecommunications Trends
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• v.38 no.2
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• pp.85-95
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• 2023

Space optical communication technology capable of large-capacity, high-speed, and low-latency communication can reduce the size, weight, and power consumption of radio frequency communications in existing satellite systems, thereby reducing launch costs, accommodating additional science instruments, and extending lifetime. Despite the high technical difficulty, various projects are being carried out in advanced countries regarding space technology for use in national security and defense, earth observation, and space communications. We review the advantages, key components, and development trends of space optical communication technology, which is attracting attention in applications such as satellite communications, intersatellite linking, and deep space communications.