• Title/Summary/Keyword: Variable-Property

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Study of Deepsea Mining Robot "MineRo" Using Table of Orthogonal Arrays (직교 배열표를 이용한 심해저 채광로봇 미내로의 주행 특성 연구)

  • Lee, Chang-Ho;Kim, Hyung-Woo;Choi, Jong-Su;Yeu, Tae-Kyeong;Lee, Min-Uk;Oh, Jae-Won;Hong, Sup
    • Journal of Ocean Engineering and Technology
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    • v.28 no.2
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    • pp.152-159
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    • 2014
  • KRISO(Korea Research Institute of Ships & Ocean Engineering) designed and manufactured a pilot mining robot called "MineRo" in 2012. MineRo is composed of four track modules. In general, much time and money are needed for deep-sea tests. Therefore, a numerical analysis to predict the dynamic behaviors has to be performed before a deep-sea test. In the numerical analysis, the information about the mining robot and soil properties are the most important factors to analyze the driving performance and dynamic response of MineRo. A terra-mechanics model of extremely cohesive soft soil is implemented in the form of the relationships between the normal pressure and sinkage, and between the shear stress and shear displacement. It is possible to acquire information about MineRo from the CAD model in the design phase. The Wong model is applied to the terra-mechanics model. This model is necessary to acquire many soil coefficients for a numerical analysis. However, in soil testing, the amount of soil property data obtained is limited. Moreover, it is difficult to analyze all of the cases for the many soil coefficients. In this paper, the dynamic behaviors of MineRo are analyzed according to the driving velocity, steering ratio, and variable extremely cohesive soft soil properties using a table of orthogonal arrays. The dynamic responses of MineRo are the turning radius, sinkage, and slip ratio. The relationships between the dynamic responses and variable soil properties are derived for MineRo.

Submarket Identification in Property Markets: Focusing on a Hedonic Price Model Improvement (부동산 하부시장 구획: 헤도닉 모형의 개선을 중심으로)

  • Lee, Chang Ro;Eum, Young Seob;Park, Key Ho
    • Journal of the Korean Geographical Society
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    • v.49 no.3
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    • pp.405-422
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    • 2014
  • Two important issues in hedonic model are to specify accurate model and delineate submarkets. While the former has experienced much improvement over recent decades, the latter has received relatively little attention. However, the accuracy of estimates from hedonic model will be necessarily reduced when the analysis does not adequately address market segmentation which can capture the spatial scale of price formation process in real estate. Placing emphasis on improvement of performance in hedonic model, this paper tried to segment real estate markets in Gangnam-gu and Jungrang-gu, which correspond to most heterogeneous and homogeneous ones respectively in 25 autonomous districts of Seoul. First, we calculated variable coefficients from mixed geographically weighted regression model (mixed GWR model) as input for clustering, since the coefficient from hedonic model can be interpreted as shadow price of attributes constituting real estate. After that, we developed a spatially constrained data-driven methodology to preserve spatial contiguity by utilizing the SKATER algorithm based on a minimum spanning tree. Finally, the performance of this method was verified by applying a multi-level model. We concluded that submarket does not exist in Jungrang-gu and five submarkets centered on arterial roads would be reasonable in Gangnam-gu. Urban infrastructure such as arterial roads has not been considered an important factor for delineating submarkets until now, but it was found empirically that they play a key role in market segmentation.

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The Impact of Business Scope and Technological Innovation Capability on Firm Performance in SMEs (중소기업의 사업영역과 기술혁신역량이 경영성과에 미치는 영향에 관한 실증연구)

  • Lee, Byeong-Heon;Kim, Yeong-Geun
    • 한국벤처창업학회:학술대회논문집
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    • 2007.04a
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    • pp.203-226
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    • 2007
  • The purpose of this research is to analyze the impact of business scope and technological innovation capability(TIC) on firm performance in SMEs. Among the 1,077 SME sample data collected with the help of Korean Industrial Complex Corporation, 228 sample data from capital goods sectors had been selected and analyzed. Several mutiple regression models were developed to test the main and the interaction effects of two independent variables business scope and TIC on SME performance. The empirical analysis show that the number of product lines, one of the two scope variable measured, is positively correlated with the return on sales(ROS). Among the variable of TIC, the number of intellectual property rights(IPRs) is positively correlated with the sales growth rates of SMEs, which the ratio of engineers to total employees is positively correlated with the ROS of SMEs. The results also delineated some interaction effects of business scope and TIC on SME performance. There exists a positive interaction effect of the ratio of engineers to total employees and the number of product lines both on ROS and scales growth rate. The interaction of the number of customers and the number of IPRs positively effects on ROS, and also the interaction of the number of product lines and the number of IPRs are positively related with ROS. Findings of this research indicates that it is necessary for SMEs in capital goods sectors to accumulate technological innovation capability and to expand business scope to improve firm performance. Furthermore, the accumulation of internal TIC should accommodate with the expansion of business scope to gain an improved performance. Particularly, adequate technological innovation capability is required to address the need of expanded customers when enlarging the scope of customers.

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Implementation of Multiple-Valued Adder and Multiplier Using Current-Mode CMOS (전류모드 CMOS에 의한 다치 가산기 및 승산기의 구현)

  • Seong, Hyeon-Kyeong
    • The KIPS Transactions:PartA
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    • v.11A no.2
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    • pp.115-122
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    • 2004
  • In this paper, the multiple-valued adders and multipliers are implemented by current-mode CMOS. First, we implement the 3-valued T-gate and the 4-valued T-gate using current-mode CMOS which have an effective availability of integrated circuit design. Second we implement the circuits to be realized 2-variable 3-valued addition table and multiplication table over finite fields $GF(3^2)$, and 2-variable 4-valued addition table and multiplication table over finite fields $GF(4^2)$ with the multiple-valued T-gates. Finally, these operation circuits are simulated under $1.5\mutextrm{m}$ CMOS standard technology, $15\mutextrm{A}$ unit current, and 3.3V VDD voltage Spice. The simulation results have shown the satisfying current characteristics. The 3-valued adder and multiplier, and the 4-valued adder and multiplier implemented by current-mode CMOS is simple and regular for wire routing and possesses the property of modularity with cell array. Also, since it is expansible for the addition and multiplication of two polynomials in the finite field with very large m, it is suitable for VLSI implementation.

An Empirical Study on Financial Characteristics of KOSDAQ Venture Companies (코스닥시장 우량벤처기업 판별모형 개발에 관한 연구)

  • Kim, Hong-Kee;Oh, Sung-Bae
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.2 no.1
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    • pp.37-64
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    • 2007
  • The purpose of this study is verifying which financial property of a venture company listed in KOSDAQ is a primary factor to determine Highly Successful company or Less Successful one. For sampling, I classified 405 venture companies, whose averages for 2005 of 2 standards are In the 30% high/low rank, as Highly Successful/Less Successful companies subject to the higher Operating Income to Total Assets and Return on Invested Capital (ROIC), the Highly Successful company. And I verified which variable is most important one to distinguish between Highly Successful companies and Less Successful ones among 24 financial ratios selected through preceding studies. For the analysis, I firstly extracted analogous variables by Stepwise Method and secondly carried out Multi variate Discriminant Analysis. The result mainly shows variables related to returns and stability similar to preceding studies. Especially, Operating Income to Total Assets reveals most reliable variable distinguishing between Highly Successful company and Less Successful one, whereas Current Ratio does not. When reliability of function formula of variables were compared with Operating Income to Total Assets standard and ROIC standard, there was almost no difference.

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Synthesis of Renewable Resource-derived Furan-based Epoxy Compounds and Their Adhesive Property (재생자원 유래 퓨란계 에폭시 화합물의 합성 및 접착 특성)

  • Lee, Jae-Soung;Lee, Sang-Hyeup;Jeong, Jaewon;Kim, Baekjin;Cho, Jin Ku;Kim, Hyun Joong
    • Journal of Adhesion and Interface
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    • v.11 no.2
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    • pp.41-49
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    • 2010
  • Furan-containing epoxide monomers (8, 9) were designed and synthesized as carbon-neutral, environment-friendly adhesion material. Bicyclic skeleton were constructed using the Diels-Alder reaction of furan and methyl acrylate, both readily accessible starting material from a biomass via bio-refinery process. After reduction of ester functionality, resulting hydroxyl moieties were coupled to epichlorohydrin to provide the epoxy-functionalized furanic monomers (8, 9). The structure of new furanic monomers was confirmed by $^1H$ and $^{13}C$ NMR spectroscopy. As UV-curable monomers, basic properties such as UV curing time and the extent of UV curing were evaluated by photo DSC. Photo-curing shrinkages were measured by linear variable differential transformer transducer (LVDT) and the effect of molecular structure on shrinkage was considered. In addition, new synthetic compounds showed the shear strength over 3 MPa when they were photo-cured between polycarbonate plates, which indicates these compounds are feasible to use as photo-curable adhesive materials.

The Design of A Fast Two′s Complement Adder with Redundant Binary Arithmetic (RB 연산을 이용한 고속 2의 보수 덧셈기의 설계)

  • Lee, Tae-Uk;Jo, Sang-Bok
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.37 no.5
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    • pp.55-65
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    • 2000
  • In this paper a new architecture of 24-bit two's complement adder is designed by using RB(Redundant Binary) arithmetic which has the advantage of CPF(Carry-Propagation-Free). A MPPL(Modified PPL) XOR/XNOR gate is applied to improve a TC2RB(Two's Complement to RB SUM converter) speed and to reduce the number of transistors, and we proposed two types adder which used a fast RB2TC(RB SUM to Two's Complement converter). The property of two types adder is followings. The improvement of TYPE 1 adder speed is archived through the use of VGS(Variable Group Select) method and TYPE 2 adder is through the use of a 64-bit GCG(Group Change bit Generator) circuit and a 8-bit TYPE 1 adder. For 64-bit, TYPE 1 adder can be expected speed improvement of 23.5%, 25.7% comparing with the CLA and CSA, and TYPE 2 adder can be expected 41.2%, 45.9% respectively. The propagation delay of designed 24-bit TYPE 1 adder is 1.4ns and TYPE 2 adder is 1.2ns. The implementation is highly regular with repeated modules and is very well suited for microprocessor systems and fast DSP units.

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A Study on the Satisfaction of Non Face to Face Real Time Education Focused on Firefighter in COVID-19 (코로나19 상황에서 소방공무원을 대상으로 한 비대면 실시간 교육 만족도에 관한 연구)

  • Park, Jin Chan;Baek, Min Ho
    • Journal of the Society of Disaster Information
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    • v.18 no.1
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    • pp.91-103
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    • 2022
  • Purpose: After COVID-19, changes in the educational ecosystem take place and fire service academy education system have shifted from face-to-face into non fact-to-face. So, the educational effect of fire officials is decreased and the satisfaction level is also decreased. In this study, we want to examine the current status of non-face-to-face real-time remote education and supplement the problems to improve the educational methods, the educational environment, etc. Method: This study is an independent variable that affects non-face-to-face real-time remote education, consisting of education system environment, self-efficacy of computers, contents (education contents, structure, design, etc.), and proper interaction. A dependent variable was selected with satisfaction for non-face-to-face real-time remote education. In addition, it was selected and analyzed as an active property of learning motivation and learning attitude as control variables. Result: The better the content and the more active the learning motivation and the attitude toward learning, the higher the satisfaction of non-face-to-face real-time remote education, and the more active the learning motivation and the attitude toward learning, the more positive the computer self-efficacy and the satisfaction of learning Conclusion: In order to increase the satisfaction of non-face-to-face real-time education due to COVID-19, education designers or professors need to provide non-face-to-face education contents that can increase the aggressiveness of their learning motivation and learning attitude, and to increase the satisfaction of education for learners by increasing computer self-efficacy through pre-education of non-face-to-face education systems.

A study on the prediction of korean NPL market return (한국 NPL시장 수익률 예측에 관한 연구)

  • Lee, Hyeon Su;Jeong, Seung Hwan;Oh, Kyong Joo
    • Journal of Intelligence and Information Systems
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    • v.25 no.2
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    • pp.123-139
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    • 2019
  • The Korean NPL market was formed by the government and foreign capital shortly after the 1997 IMF crisis. However, this market is short-lived, as the bad debt has started to increase after the global financial crisis in 2009 due to the real economic recession. NPL has become a major investment in the market in recent years when the domestic capital market's investment capital began to enter the NPL market in earnest. Although the domestic NPL market has received considerable attention due to the overheating of the NPL market in recent years, research on the NPL market has been abrupt since the history of capital market investment in the domestic NPL market is short. In addition, decision-making through more scientific and systematic analysis is required due to the decline in profitability and the price fluctuation due to the fluctuation of the real estate business. In this study, we propose a prediction model that can determine the achievement of the benchmark yield by using the NPL market related data in accordance with the market demand. In order to build the model, we used Korean NPL data from December 2013 to December 2017 for about 4 years. The total number of things data was 2291. As independent variables, only the variables related to the dependent variable were selected for the 11 variables that indicate the characteristics of the real estate. In order to select the variables, one to one t-test and logistic regression stepwise and decision tree were performed. Seven independent variables (purchase year, SPC (Special Purpose Company), municipality, appraisal value, purchase cost, OPB (Outstanding Principle Balance), HP (Holding Period)). The dependent variable is a bivariate variable that indicates whether the benchmark rate is reached. This is because the accuracy of the model predicting the binomial variables is higher than the model predicting the continuous variables, and the accuracy of these models is directly related to the effectiveness of the model. In addition, in the case of a special purpose company, whether or not to purchase the property is the main concern. Therefore, whether or not to achieve a certain level of return is enough to make a decision. For the dependent variable, we constructed and compared the predictive model by calculating the dependent variable by adjusting the numerical value to ascertain whether 12%, which is the standard rate of return used in the industry, is a meaningful reference value. As a result, it was found that the hit ratio average of the predictive model constructed using the dependent variable calculated by the 12% standard rate of return was the best at 64.60%. In order to propose an optimal prediction model based on the determined dependent variables and 7 independent variables, we construct a prediction model by applying the five methodologies of discriminant analysis, logistic regression analysis, decision tree, artificial neural network, and genetic algorithm linear model we tried to compare them. To do this, 10 sets of training data and testing data were extracted using 10 fold validation method. After building the model using this data, the hit ratio of each set was averaged and the performance was compared. As a result, the hit ratio average of prediction models constructed by using discriminant analysis, logistic regression model, decision tree, artificial neural network, and genetic algorithm linear model were 64.40%, 65.12%, 63.54%, 67.40%, and 60.51%, respectively. It was confirmed that the model using the artificial neural network is the best. Through this study, it is proved that it is effective to utilize 7 independent variables and artificial neural network prediction model in the future NPL market. The proposed model predicts that the 12% return of new things will be achieved beforehand, which will help the special purpose companies make investment decisions. Furthermore, we anticipate that the NPL market will be liquidated as the transaction proceeds at an appropriate price.

A Study on the Phase-looked Dielectric Resonator Oscillator using Bias Tuning (바이어스 동조를 이용한 위상 고정 유전체 공진 발진기에 관한 연구)

  • 류근관;이두한;홍의석
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.10
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    • pp.1982-1990
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    • 1994
  • We implemented a PLDRO(Phase Locked Dielectric Resonator Oscillator) using the concept of the feedback property of PLL(Phase Locked Loop) for Ku-band(10.95-11.70 GHz). The conventional approaches to a PLDRO design use varactor diode tuning method.. But in theis paper, the PLDRO has the advantage of the frequency sensitivity to changes in the supple voltage of the oscillating device without the frequency-variable part by varactor diode voltage-control. and uses a SPD(Sampling Phase Detector) for phase-comparision. The PLDRO is composed of the DRO phase-locked to the reference signal of UHF band by using a SPD for high frequency stability and can be available for European FSS(Fixed Satellite Service) at 10.00GHz. The PLDRO generates the output power of 8.67 dBm at 10.00 GHz and has a phase noise of -81 dBc/Hz at 10 kHz offset from carrier. The hamonic and spurious characteristics have -42.33 dBc and -65dBc respectively. This PLDRO has much better frequency stability, lower phase noise, and more economical effect for a satellite system than conventional DRO.

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