• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.5
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• pp.653-658
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• 2013

For towing the new type armored vehicle and maintaining the close support, the armored recovery vehicle(ARV) with winch and crane has been developed. In case of crane, it is mainly used to salvage heavy objects by rotational and vertical motion. Especially, the crane bracket is very important parts due to fixing the ARV's body and rotary joint and preventing the force rotation of crane. Therefore, the crane bracket needs to have an enough strength to endure the high load and it is very important to analyze the stress distribution under loads. In the present work, the experimental and analytical investigation on structural integrity evaluation of crane bracket were carried out. The simulation of three-dimensional finite element method(FEM) was compared with experimental datum. From the numerical results, the FEM simulations corresponded well with th experimental results and the structural safety was confirmed by safety factor.

• Honam Mathematical Journal
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• v.3 no.1
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• pp.41-60
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• 1981

다양체(多樣體)의 연구(硏究)에서 벡터속(束)의 개념(慨念)은 불가결(不可缺)하며 벡터속(束)의 연구(硏究)에는 엽층구조(葉層構造)의 연구(硏究)가 중요(重要)하다. 본(本) 논문(論文)은 권(圈) $\varrho$(M)의 응사보편공간(凝似普遍空間)에 관한 연구(硏究)(정리(定理) 4.8)로서 R. Bott의 엽층구조(葉層構造)에 관한 연구(硏究)([1])에서 착상(着想)된 것이다. 제이(第二), 삼절(三節)은 제사절(第四節)을 위한 준비(準備)로서, 제이절(第二節)에서는 벡터속(束)및 접속(接續)에 관한 성질(性質)을 논하고, 제삼절(第三節)에서는 위상권(位相圈), 층(層), 엽층구조(葉層構造) 및 $\Gamma_{q}$-cocycle 등에 관한 성질(性質)(명제(命題) 3.5, 3.7과 3.11)을 밝히고, 위상권(位相圈)의 구체적(具體的)인 예(例)(예(例)3.2, 3.3과 3.12)를 들었다. 제사절(第四節)에서는 $GL_{q}-cocycle$, 위상권(位相圈) $GL_{q}$, 집합(集合) $I_{so}(M_{k},\;GL_{q})$, $H^{1}(M_{k},\;GL_{q})$, $I_{so}(\varrho(M))$ 및 응사보편공간(凝似普遍空間)을 정의(定義)하고, 주정리(主定理) 4.8의 증명(證明)에 필요(必要)한 명제(命題)를 몇 개 기술(記述)하였다(명제(命題) 4.2, 4.5와 보제(補題) 4.9).

• Korean Journal of Environment and Ecology
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• v.10 no.1
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• pp.66-75
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• 1996

To propose basic information for national resource management and planting disign, plant community structure of evergreen broad-leaved forest was investigated. Fifty-two plots(each size 300m$^{2}$) were set up at Ch'omch'alsan area of Chindo, Korea. TWINSPAN and DCA methods were used for classification and ordination analysis. Fifty-two plots were divided into seven groups, which were Quercus variabilis-Carpinus tschonoskii community, Q. glauca community, Castanepsis cuspidata var. sieboldii-Q. stenophylla community, Castanopsis cuspidata var. sieboldii-Camelia japonica community, Q. acuta-Camelia japonica community, Carpinus coreaca-Q spp. community, C. coreana community. Pinus densiflora almost have been selected. Carpinus tschomoskii, Q. variabillis and Q. serrata were to be succeeded by Castanea cuspidata var. sieboldii, Q. stenophylla, Q. acuta and Neolitsea sericea in canopy layer. And Neolitsea sericea, Q. glauca and Camellia japonica was showed high importance values in fertile soil condition. Future restoration plan was necessary for a tourist resort or national forest in warm temperate region. And evergreen broad-leaved plants shall be planted in considering of environmental condition at warm temperate and industrial complex area.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.3
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• pp.311-320
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• 2008

In this paper, a new variable active inductor using a conventional grounded active inductor with feedback variable LC-resonator is proposed. The grounded active inductor is realized by the gyrator-C topology and the variable LC-resonator is realized by the low-Q spiral inductor and varactor. This variable LC-resonator can compensate the degradation of Q-factor due to parasitic capacitance of a transistor, and the frequency range with high Q-factor is adjustable by resonance frequency adjustment of LC-resonator. The fabricated variable active inductor with Magnachip $0.18{\mu}m$ CMOS process shows that high-Q frequency range can be adjusted according to varactor control voltage from 4.66 GHz to 5.45 GHz and Q-factor is higher than 50 in the operating frequency ranges. The measured inductance at 4.9GHz can be controlled from 4.12 nH to 5.97 nH by control voltage.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.2
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• pp.18-26
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• 2015

In this paper, we studied the method for analyzing and estimating the parameters that induce I/Q imbalance in the repeater using direct conversion RF. In repeater, amplitude, phase, and filter mismatch are generated in the receiving-end which converts RF signal to baseband signal. And amplitude and phase mismatch are generated in the transmitting-end which converts baseband signal to RF signal. Accordingly, we modeled the parameters that cause I/Q imbalance in the structure of the repeater in order, and proposed a feedback test structure from the transmitting-end to the receiving-end for estimating the corresponding parameters. By comparing the test transmitting signal and received signal, it is possible to estimate the I/Q imbalance parameters which occurred from mixed components of real and imaginary part. And it was confirmed that I/Q imbalance phenomenon has been properly compensated with estimated parameters at the direct conversion RF repeater.

• 건축구조
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• v.9 no.3
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• pp.59-61
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• 2002

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.7
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• pp.661-668
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• 2004

A novel method to reject the spurious signals which are occurred at Weaver-type low-IF transmitter was proposed in this paper. The spurious signals are generated by the gain and phase imbalances of I/Q channel or imperfect characteristics of 90$^{\circ}$ phase shifter in local oscillator for I/Q channel source. By deriving the gain and phase-based functions from RF spurious signal with the channel imbalance information, the lie channel imbalances were deduced as functions with magnitude and sign dependent on I/Q channel imbalance degree. The proposed method compensates the estimated I/Q channel imbalances by correlation values between the down-converted signal obtained by squaring the output signal itself using a simple mixer and the modified baseband signal. By comparing two signals after A/D conversion, the magnitude and sign of each type of imbalances can be determined separately and simultaneously. Based on the I/Q channel imbalance compensation, the spurious signals can be reduced by adjusting the gain and phase values of I or Q channel signal. The way to estimate the channel imbalances of the up-conversion mixer was presented and verified by using theoretical derivations and computer simulations.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.4
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• pp.266-269
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• 2018

A compact Q-band waveguide-to-microstrip transition for UAV(Unmanned Aerial Vehicle) radiometer applications is presented. The key features of this transition are simplicity, compactness, easy matching, and lower sensitivity to the dimensions and fabrication tolerances. The simple E-plane patch-type design is insensitive to the backshort cavity enclosure and misalignment between the waveguide and microstrip substrate. The primary parameters are optimized using a three-dimensional(3D) electromagnetic simulator(ANSYS HFSS). It exhibited better than 20-dB return loss at mid-band frequencies with less than 1-dB insertion loss for the back-to-back transition, and a return loss better than 15 dB over the frequency range of 36 GHz to 42 GHz.

• Korean Journal of Environment and Ecology
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• v.28 no.1
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• pp.33-44
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• 2014

The purpose of this study was to provide basic information and investigate a vegetation structure around Tohamsan (Mt.) Wetland. Actual vegetation map was made on the basis of watershed around that. Vegetation structure survey was carried out for 8 representative communities of actual vegetation which were Pinus densifrora community, Quercus variabilis community, Cornus controversa community, Q. serrata community, Q. mongolica-Q. serrata community, Salix koreensis community, Q. mongolica community, Q. variabilis-Q. mongolica-Q. serrata community. Tohamsan (Mt.) Wetland is located on 490m above sea level and the area of watershed was $236,272m^2$. Vegetation type were divided into 16 types, and the ratio of Q. mongolica community was 33.1% ($78,209.2m^2$). In order to turn out the structure of 8 representative communties, 32 plots were set up and unit area of plot was $100m^2$. The estimated age of forest is 30~50-years-old, and in the resutls of soil analysis, acidity was pH 4.89 and organic matter was 4.46%.

• Journal of Intelligence and Information Systems
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• v.12 no.1
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• pp.107-123
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• 2006

We propose the Generalized Binary Second-order Recurrent Neural Networks(GBSRNNf) being equivalent to regular grammars and ?how the implementation of lexical analyzer recognizing the regular languages by using it. All the equivalent representations of regular grammars can be implemented in circuits by using GSBRNN, since it has binary-valued components and shows the structural relationship of a regular grammar. For a regular grammar with the number of symbols m, the number of terminals p, the number of nonterminals q, and the length of input string k, the size of the corresponding GBSRNN is $O(m(p+q)^2)$ and its parallel processing time is O(k) and its sequential processing time, $O(k(p+q)^2)$.