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

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.27 no.10
• /
• pp.877-882
• /
• 2016

In this paper, a novel CMOS high Q factor 2-port active inductor has been proposed. The proposed circuit is designed by cascading basic gyrator-C structural active inductors and attaching the feedback LC resonance circuit. This LC resonator can compensate parasitic capacitance of transistor and can improve Q factor over wide frequency range. The proposed circuit was fabricated and simulated using 65 nm Samsung RF CMOS process. The fabricated circuit shows inductance of above 2 nH and Q factor higher than 40 in the frequency range of 1~6 GHz.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2019.07a
• /
• pp.393-394
• /
• 2019

본 연구는 현재 임신 중인 임산부 중 6개월 이상의 임산부를 대상으로 스스로가 본인의 체형을 어떻게 인식하고 있는가 하는 주관적 평가를 유형화하고 유형별 특성을 고찰하고자 하였다. 이를 통해 임산부의 체형에 적합한 의복디자인 및 패턴설계에 필요한 기초자료를 제공하고자 하였다. 본 연구는 Q방법론을 사용하였으며, Q분석은 쿼넬 프로그램(QuANL pc program)을 사용하였다. 임산부의 체형에 대한 인식 유형은 가는 팔다리 중앙 반구형 복부 체형, 처진 복부 돌출 체형, 굵은 윗팔 중앙 돌출 복부 체형의 3가지 유형으로 분석되었다. 가는 팔다리 중앙반구형 복부 체형은 임신 전 BMI지수가 가장 낮아 정상에 속하였으며 팔다리는 가늘고 다른 부위는 거의 살이 찌지 않았으며 배만 나왔다고 인식하였다. 처진 복부 돌출 체형은 임신 전 BMI 지수가 가장 높아 과체중에 속한 유형으로 가슴둘레, 엉덩이둘레뿐만 아니라 몸에 전체적으로 살이 쪘으며, 배가 아래로 처진 체형으로 인식되었다. 굵은 윗팔 중앙 돌출 복부 체형은 제1유형과 같이 복부의 중앙부분이 돌출되어 있다고 인식하였으나 윗팔둘레가 굵어졌다고 인식하여 제1유형과는 차이를 나타냈다. 임신 전 BMI 지수는 중간인 그룹으로 정상에 속하였다. 향후 연구에서는 임산부의 실제 체형 분석을 통하여 본 연구의 인식체형과의 차이를 비교 분석해보는 것도 의미 있는 연구가 될 것으로 생각된다.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.14 no.1
• /
• pp.1-14
• /
• 1978

To study the fluctuation of cold water in the East China Sea in summer heat budget of the Yellow Sea in winter was analysed based on the oceanographic and meteorological data compiled from 1951 to 1974. The maintain value of insolation was observed in December($160{\sim}190ly/day$), while the maximum in February ($250{\sim}260ly/day$). The range of the annual variation was found to be less than 50 ly/day. The value of the radiation term ($Q_s-Q_r-Q_h$) was remarkably small (mean 20 ly/day) in winter. It was negative value in December and January, and a positive value in February. The minimum total heat exchange from the sea ($Q_({h+c}$) was found value (471 ly/day) in February 1962, and the maximum (882 ly/day) in January 1963. The annual total heat exchange was minimum (588 ly/day) in 1962, and maximum (716 ly/day) in 1968. If the average deviation of mean water temperature at 50m depth layer were assumed to be the horizontal index ($C_h$) of colder water, $C_h$ is $C_h=\frac{{\Sigma}\limit_i\;A_i\;T_i}{{\Sigma}\limit_i\;A_i}$ where $A_i$ denotes the area of isothermal region and $T_i$ the value of deviation from mean sea water temperature. The vertical index ($C_v$) of cold water can be expressed similarly. Consequently the total index (C) of cold water equals to the sum of the two components, i.e. $C=C_h$＋$C_v$. Taking the deviation of mean sea surface temperature(T'w) in the third ten-day of Novembers in the Yellow Sea as the value of the initial condition, the following expressions are deduced : $C－T'w＝32.06 - 0.049$ $\;Q_T$ $C_h-T'w/2=12.20-0.019\;Q_T$ $C_v-T'w/2＝18.07-0.027\;Q_T$ where $Q_T$ denotes the total heat exchange of the sea. The correlation coefficients of these regression equations were found to be greater than 0.9. Heat budget was 588 ly/day in winter, and minimum water temperature of cold water was $18^{\circ}C$ in summer of 1962. The isotherm of $23^{\circ}C$ extended narrowly to southward up to $29^{\circ}N$ in summer. However, heat budget was 716 ly/day, and minimum water temperature of cold water was $12^{\circ}C$ in summer of 1968. The isotherm of $23^{\circ}C$ extended widely to southward up to $28^{\circ}30'N$ in summer. As a result of the present study, it may be concluded that the fluctuation of cold water of the East China Sea in summer can be predicted by the calculation of heat budget of the Yellow Sea in winter.

• Journal of Wetlands Research
• /
• v.19 no.1
• /
• pp.164-171
• /
• 2017

This study analysed 7 distribution features of dominant natural vegetation, such as elevation, slope, aspect, topographic index, annual mean temperature, warmth index and potential evapotranspiration using geographic information system(GIS) in Gayasan national park. The Gayasan national park has total 128 communities in which Pinus densiflora community occupies with 29.42%, Quercus mongolica community 27.66% relatively. These two communities comprise 80.58% out of total area, considering Q. mongolica & P. densiflora dominantly mixed communities. The Q. mongolica communities range around 575~1,065m(80.4%) in elevation, and the P. densiflora communities range around 465~965m(84.1%), respectively. The slopes of those two communities areas showed over $21^{\circ}$(78.0%) and (71.3%) respectively. In terms of slope aspect occurrence, Q. mongolica communities occur mostly on northern slope, and the P. densiflora communities on southern slope. The topographic indices of both communities occur around 5~6 most frequently. The Annual mean temperature distributions of Q. mongolica and P. densiflora range $7{\sim}8^{\circ}C$(83%), $8{\sim}9^{\circ}C$(84%), respectively, And the warmth index range of Q. mongolica is $59{\sim}70^{\circ}C{\cdot}month$ and the P. densiflora community, $58{\sim}88^{\circ}C{\cdot}month$. The potential evapotranspiration ranges mostly from 560 to 590mm/yr, in Q. mongolica communities, and from 580 to 610mm/yr in P. densiflora communities.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.9
• /
• pp.251-260
• /
• 2018

The purpose of this study was to determine the association of the Body Shape Index (ABSI) with suicide ideation and suicide attempts by controlling the body mass index (BMI), as well as general characteristics that may affect suicide. The study has used The Sixth Korea National Health and Nutrition Examination Survey conducted by the Korea Centers for Disease Control and Prevention from 2013 to 2015. A total of 13,155 participants were studied, excluding those who had no information on variables that could affect suicidal ideations and suicidal attempts. The chi-squared test and the multivariate logistic regression analysis were performed. The results of the analysis showed that those who had obesity in BMI were more likely to commit suicide and suicide than those who were in 'standard' in BMI. In ABSI, Q3 group was more likely to commit suicide than Q1 group. The number of suicide attempt was significantly higher in the group with Q3 in ABSI than in Q1 group (3.623 times (95% CI 1.027-12.772)). The results of this study suggest that a higher ABSI compared to BMI means that it is possible to make a more extreme choice of suicide attempt rather than suicide ideation.

• KOREAN POULTRY JOURNAL
• /
• v.51 no.6
• /
• pp.199-199
• /
• 2019

• Journal of Digital Convergence
• /
• v.16 no.12
• /
• pp.137-145
• /
• 2018

The purpose of this study is to identify the CSR activities and to investigate the relationship between CSR activities and business performance. Specifically, we analyzed the companies that were included in the SRI index as CSR activity companies, and analyzed how they affect the business performance of the companies according to SRI index incorporation disclosure. As a result of the analysis, the SRI index incorporation announcement has a significant positive effect on the corporate value(Tobin's Q) but it has not significant effect on the financial performance(ROA). This suggests that CSR activities are offered to companies' managers and stakeholders as a basis for investment rather than expense. In the future research, it will be more meaningful if the study on the intention to participate in CSR activities is conducted based on this study and previous studies.

• Journal for History of Mathematics
• /
• v.31 no.4
• /
• pp.183-196
• /
• 2018

In this study, we propose an approximate method to make Jisuguimundo with magic number 93 to 109. In this method, for two numbers p, q with a relationship of M = 2p+q, we use eight pairs of two numbers with sum p and five pairs of two numbers with sum q. Such numbers must be between 1 and 30. Instead of determining all positions of thirty numbers, this method shows that Jisuguimundo with magic number 93 to 109 can be made by determining positions of thirteen numbers $a_i$(i = 1, 2, ${\cdots}$, 8), $b_5$, $c_i$(i = 1, 2, 3, 4). Method 1 is used to make Jisuguimundo with magic number 93 to 108, and method 2 is used to make Jisuguimundo with magic number 109.

• Proceedings of the KSRS Conference
• /
• 2009.03a
• /
• pp.82-86
• /
• 2009

원격탐사 근적외선(NIR)과 Red 밴드의 반사도로부터 계산되는 정규식생지수(NDVI)는 구름에 오염된 곳에서는 실제보다 낮은 값으로 계산된다. 식생지수에서 구름오염 문제를 극복하는 기존의 대표적인 방법에는 보름 정도 장기간 식생지수 값 중에서 최대인 값을 취하는 MVC(Maximum Value Composite) 방법이 있다. 하지만 MVC 방법으로는 식생지수의 단기간 변동을 파악할 수 없으며, 장기간 계속 구름으로 오염된 곳은 잘못된 식생지수 값으로 계산되는 문제점이 있다. 가시광 RGB 자료로부터 snapshot 영상자료의 구름을 마스크(mask)하는 새로운 방법인 CIM(Color Index Manipulation) 알고리즘을 개발하였다. 이 알고리즘을 사용하면 snapshot 영상자료에서 구름에 오염된 곳은 제외하고 오염되지 않은 곳에 대한 식생지수를 계산할 수 있다. RGB 자료에 대한 정규색상지수 NCI (Normalized Color Index) 3개 성분을 $120^{\circ}$ 간격으로 벌어진 3개 축상의 좌표로 나타낸 후 이들 3개 값의 벡터합(vector sum) 정보를 이용하여 구름을 식별하는 CIM 방법으로 위성영상에서 두꺼운 구름과 않은 구름을 구분하여 식별할 수 있다. 이 구름식별 기법을 MODIS snapshot 위성영상 자료에 적용하여 한반도의 일별(daily) 식생지수 자료를 계산하였다. 그리고 수년간의 일별 식생지수 자료로부터 한반도 식생지수의 계절적 변동을 조사하였다.