• Journal of information and communication convergence engineering
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• 제16권1호
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• pp.12-16
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• 2018

In this work, a voltage controlled oscillator (VCO) monolithic microwave integrated circuit (MMIC) was demonstrated for 10-GHz band motion detecting sensors. The VCO MMIC was fabricated using a $2-{\mu}m$ InGap/GaAs HBT process, and the tuning of the oscillation frequency is achieved by changing the internal capacitance in the HBT, instead of using extra varactor diodes. The implemented VCO MMIC has a micro size of $500{\mu}m{\times}500{\mu}m$, and demonstrates the value of inserting the VCO into a single chip transceiver. The experimental results showed that the frequency tuning characteristic was above 30 MHz, with the excellent output flatness characteristic of ${\pm}0.2dBm$ over the tuning bandwidth. And, the VCO MMIC exhibited a phase noise characteristic of -92.64 dBc/Hz and -118.28 dBc/Hz at the 100 kHz and 1 MHz offset frequencies from the carrier, respectively. The measured values were consistent with the design values, and exhibited good performance.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2008년도 학술대회 2부
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• pp.436-441
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• 2008

오늘날의 오피스 공간은 오피스 초창기에 보여지 듯 거대한 공간 안에서 동시다발적으로 일어났던 공간 구조와는 달리 개인의 업무, 공동의 업무와 상호 독립적인 업무, 그룹의 업무방법과 그룹문화, 그룹과 사람에 따라서 다르게 구성하고 있다. 이는 산업과 기술의 발달로 하여금 사용자의 오피스 공간 의식변화 및 공간 형태에서 큰 변화가 이루어짐을 의미한다. 하지만 유비쿼터스 기술의 빠른 성장은 건물 전체의 기능이나 성능, 효율과 더불어 사용자 중심의 공간의 서비스를 제공하는 지능형오피스의 기술적 공간변화로 진화되고 있다. 본 논문에서는 지능형오피스의 개념을 구체화와 사용자요구 중심의 오피스환경 연구의 일환으로 지능형오피스 서비스시나리오 구성에 대한 연구를 진행하였다.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2008년 추계학술발표대회 논문집
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• pp.344-349
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• 2008

When it comes to discussing the natural behaviors of human life, defining the word "community" itself can be extremely crucial. The word "Community" can be defined as a group of interacting human beings sharing an environment. It is also the basic form for "dwelling" which can be explained as a quint essential factor in human life. Compared to the previous traditional society with strong bonding and close chemistry between neighbors, modern society with simple and monolithic apartments brought a literal extinction of what has been called as a 'relationship'. Hence, people started to take this phenomenon as a problematic issue. Also, high-rise apartments made its residents more isolated and individualistic on a growing basis. In order to aid the aggravating symptoms, there has been a wide recognition between the "dwellers" to develop and strengthen their "community". This movement in strengthening the "community" is currently on a full expansion towards the cyber space, riding the tides of a drastic improvement of the Internet. Apartment web sites today not only displays introductory level of information they also provide wider meanings of general lifestyle plus deeper content, which can enhance their community.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2008년 추계학술발표대회 논문집
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• pp.397-402
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• 2008

For the past years, Korean Housing policy have been focused on quantity rather then quality, when they provide housing. Focusing great quantity on housing led monolithic and standardized house forms in limited area. Most of our traditional residental environment, which made Koreans to communicate with neighbors, disappeared from the result of providing great quantity on housing. However, the increase of the income and standard of living, changed people's view. People start to demand for the place which is commodious and comfortable to live. Moreover, more leisure time caused people to communicate with their neighbors. To meet the demands of new forms of housing, they started to provide a community space to increase sense of belonging and community spirit for the residents in apartment house. The forms of past house which is defined by uniformity is delivered from rational thoughts. People can get emotional satisfaction from Community space because it provides opportunity of communicating and increase community spirit. This research is to classify the emotional expression in Community space and analyze the elements that is expressed in community space of apartment house.

• 한국세라믹학회지
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• 제33권11호
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• pp.1285-1291
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• 1996

Using Cr2O3 Al and graphite powders as starting materials Cr3C2 was synthesized by combustion synthesis process according to the following reaction : 3Cr3C2 +4C+6Allongrightarrow2Cr3C2 +3Al2O3. The synthesis was conducted at 2 atm in an argon atmosphere. in this study main-product was monolithic phase of Cr3C2 /Cr7C3 mixture and sub-product was slag state of $\alpha$-Al2O3. Single phase of Cr3C2 was obtained when crushed main-product was heat-treated at 120$0^{\circ}C$ for 3h in vacuum state with addition of 2.5wt% C. The obtained Cr3C2 powder can be used as plasma-arc deposit material because the flowability index of powder with the size of 9-50${\mu}{\textrm}{m}$ was 66.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.411-412
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• 2008

The high performance 94 GHz MMIC(Monolithic Micro-wave Integrated Circuit) single balanced mixer was designed and fabricated, using MHEMT structure based diodes and a CPW(Coplanar Waveguide) tandem coupler. A novel single-balanced structure of diode mixer is proposed in this work, where a 3-dB tandem coupler with two section of parallel-coupled line. Implemented air-bridge crossover structures achieve wide frequency operation and the fabricated mixer exhibits excellent LO-RF isolation, larger than 30 dB, in the 5 GHz bandwidth of 91-96 GHz. A good conversion loss of 7.4 dB is measured at 94 GHz. The proposed MHEMT-based diode mixer shows superior LO-RF isolation and conversion loss to those of the W-band mixers reported to date.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.1062-1065
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• 2002

We demonstrate the MMIC(monolithic microwave integrated circuit) frequency doublers generating stable and low-cost 29 ㎓ local oscillator signals from 14.5 ㎓ input signals. These devices were designed and fabricated by using the MMIC integration process of 0.1 $\mu\textrm{m}$ gate-length PHEMTs (pseudomorphic high electron mobility transistors). The measurements showed S$\_$11/ of -9.2 dB at 14.5 ㎓, S/sub22/ of -18.6 dB at 29 ㎓ and a minimum conversion loss of 18.2 dB at 14.5 ㎓ with an input power of 6 dBm. The fundamental signal of 14.5㎓ was suppressed below 15.2 dBc compared with the second harmonic signal at the output port, and the isolation characteristics of the fundamental signal between the input and the output port were maintained above 30 dB in the frequency range of 10.5 ㎓ to 18.5 ㎓.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.1296-1299
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• 2002

We implemented a CD signal processor operated on a CAV 48-speed CD-ROM drive into a VLSI. The CD signal processor is a mixed mode monolithic IC including servo-processor, data recovery, data-processor, and I-bit DAC. For servo signal processing, we included a DSP core, while, for CAV mode playback, we adopted a PLL with a wide recovery range. Data processor (DP) was designed to meet the yellow book specification.［2］So, the DP block consists of EFM demodulator, C1/C2 ECC block, audio processor and a block transferring data to an ATAPI chip. A modified Euclid's algorithm was used as a key equation solver for the ECC block To achieve the high-speed decoding, the RS decoder is operated by a pipelined method. Audio playability is increased by playing a CD-DA disc at the speed of 12X or 16X. For this, subcode sync and data are processed in the same way as main data processing. The overall performance of IC is verified by measuring a transfer rate from the innermost area of disc to the outermost area. At 48-speed, the operating frequency is 210 ㎒, and this chip is fabricated by 0.35 um STD90 cell library of Samsung Electronics.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.1137-1140
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• 2002

A V-band low-noise amplifiers (LNA) based on the Millimeter-wave monolithic integrated circuit (MIMIC) technology were fabricated using high performance 0.1 $\mu\textrm{m}$ $\Gamma$-shaped pseudomorphic high electron mobility transistors (PHEMT＇s), coplanar waveguide (CPW) structures and the integrated process for passive and active devices. The low-noise designs resulted in a two-stage MIMIC LNA with a high S$\sub$21/ gain of 14.9 dB and a good matching at 60 ㎓. 20 dBm of IP3 and 3.9 dB of minimum noise figure were also obtained from the LNA. The 2-stage LNA was designed in a chip size of 2.3 ${\times}$1.4 mm$^2$by using 70 $\mu\textrm{m}$ ${\times}$2 PHEMT’s. These results demonstrate that a good low-noise performance and simultaneously with a high gain performance is achievable with GaAs PHEMT's in the 60 ㎓ band.

• 한국공작기계학회논문집
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• 제17권1호
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• pp.1-6
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• 2008

There are some methods that have been used to manage a degasing process in recent years, such as an injection method that uses aluminum molten metal powder and chemicals supplier and input method that supplies argon and nitrogen, or chlorine gas by using a gas blow-tube. However, these methods show some problems, and it shows that it is a difficult process to handle, pollution due to producing a lot of toxic gases like chlorine and fluoride gas, irregular effects, and lowering work efficiency due to the excessive processing time. The problems that are the most fatal are the producing a lot of sludge due to the reaction of aluminum molten metal with chemicals, loss of metals, and decreasing the life of refractory materials. In order to solve these problems, this paper develops a technology that is related to aluminum continuous casting molten metal and monolithic degasing apparatus. A degasing apparatus developed in this study improved the existing methods and prevented environmental pollution with smokeless, odorless, and harmlessness by using a new method that applies argon and nitrogen gas in which the methods used in the West and Japan are eliminated. The method developed in this study decreases the molten metal processing and settling time compared to the existing methods and improves the workers' health, safety, and environment because there is no pollution in processes.