• Title/Summary/Keyword: 산학서(算學書)

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A study on improving the bike way in the Urban river Waterfront (도시하천 수변공간 내 자전거도로 개선방안 연구)

  • Seo, Yong-Soo;Dong, Jae-Uk;Cho, Sung-Hak
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.5
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    • pp.481-489
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    • 2017
  • The study area,Cheonan Stream, is an urban river that flows through urban areas in close proximity to densely populated areas and multi-use facilities. The natural river improvement project from 2006 to 2015 improved the quality of life of local residents with the improvement of river function, the restoration of the natural ecosystem and the securement of hydrophilic space. A bike way in the constructed waterside space was built focusing on trails. This study suggests improvements appropriate for insufficient bike way function-related regulations. The problems of ramps, river crossing facilities, stairway facilities, safety facilities, signs, road markings, and parking facilities, etc.have arisen in the utilization situation and citizen consciousness survey. As an improvement, it was suggested that 12% or fewer ramps should be improved, a submerged bridge should be installed at 7 places separated by stepping bridges, and signs and road markings according to bike way-related regulations should be installed and bike parking facilities at Cheonan station and Cheonan bus terminal should be expanded. The bike way in the waterfront of ChoenanCheon(river) will increase the accessibility and utilization rate of short-distance transportation with the institutional expansion of bike use facilities and work organizations and the improvement of facilities in accordance with urban rivers and bike-related regulations. Therefore, it is expected that the development of the living space will be beneficial for the citizens due to the elimination of traffic in the city and the activation of bike traffic.

A Study on Combustion and Emission Characteristics of a Diesel Engine Fuelled with Pyrolysis Oil-Ethanol and Pilot Diesel (바이오원유-에탄올/파일럿 디젤유 이종연료 혼소를 통한 디젤엔진의 연소 및 배출가스 특성에 관한 연구)

  • Kim, Min-Jae;Lee, Seok-Hwan;Cho, Jeong-Kwon;Yoon, Jun-Kyu;Lim, Jong-Han
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.5
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    • pp.420-427
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    • 2017
  • Recently, the depletion of fossil fuels, global warming and environmental pollution have emerged as a worldwide problem, and studies of new renewable energy sources have been progressed. Among the many renewable energy sources, the use of bio fuel has the potential to displace fossil fuels due to low price, easy to handle, and the abundant sources. Pyrolysis oil (PO) derived from waste wood and sawdust is considered an alternative fuel for use in diesel engines. On the other hand, PO is limited to diesel engines because of its low cetane number, high viscosity, high acidity, and low energy density. Therefore, to improve its poor properties, PO was mixed with alcohol fuels, such as ethanol. Early mixing with ethanol has the benefit of improving the storage and handling properties of the PO. Furthermore, a PO-ethanol blended fuel was injected separately, which can be fired through pilot-injected diesel in a dual-injection diesel engine. The experimental results showed that the substitution of diesel with blended fuel increases the amount of HC and CO, but reduces the NOx and PM significantly.

A Study on the quantitative measurement methods of MRTD and prediction of detection distance for Infrared surveillance equipments in military (군용 열영상장비 최소분해가능온도차의 정량적 측정 방법 및 탐지거리 예측에 관한 연구)

  • Jung, Yeong-Tak;Lim, Jae-Seong;Lee, Ji-Hyeok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.5
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    • pp.557-564
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    • 2017
  • The purpose of the thermal imaging observation device mounted on the K's tank in the Republic of Korea military is to convert infrared rays into visual information to provide information about the environment under conditions of restricted visibility. Among the various performance indicators of thermal observation devices, such as the view, magnification, resolution, MTF, NETD, and Minimum Resolvable Temperature Difference (MRTD), the MRTD is the most important, because it can indicate both the spatial frequency and temperature resolvable. However, the standard method of measuring the MRTD in NATO contains many subjective factors. As the measurement result can vary depending on subjective factors such as the human eye, metal condition and measurement conditions, the MRTD obtained is not stable. In this study, these qualitative MRTD measurement systems are converted into quantitative indicators based on a gray scale using imaging processing. By converting the average of the gray scale differences of the black and white images into the MRTD, the mean values can be used to determine whether the performance requirements required by the defense specification are met. The (mean) value can also be used to discriminate between detection, recognition and identification and the detectable distance of the thermal equipment can be analyzed under various environmental conditions, such as altostratus, heavy rain and fog.

The Major Common Technology Field Analysis of Domestic Mobile Carriers based on Patent Information Data (특허 자료 정보 기반 국내 이동통신 사업자 주요 공통 기술 분야 분석)

  • Kim, Jang-Eun;Cho, Yu-Seup;Kim, Young-Rae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.5
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    • pp.723-737
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    • 2017
  • In order to decide the national technical standards policy for national policy/market economy activities, the people in charge commonly make policy decisions based on the current technology level/concentration/utilization by means of major common technology field analysis using patent data. One possible source of such patent data is the domestic mobile carriers through the Korea Intellectual Property Rights Information System (KIPRIS) of the Korean Intellectual Property Office (KIPO). Using this system, we collected 20,294 patents and 152 International Patent Classification (IPC) types and confirmed KTs (9,738 cases / 47.98%), which perform relatively high technology retention activities compared to other mobile carriers through the KIPRIS of KIPO. Based on these data, we performed three analyses (SNA, PCA, ARIMA) and extracted 30 IPC types from the SNA and 4 IPC types from the PCA. Based on the above analysis results, we confirmed that 4 IPC (H04W, H04B, G06Q, H04L) types are the major common technology field of the domestic mobile carriers. Finally, the number of 4 IPC (H04W, H04B, G06Q, H04L) forecast averages of the ARIMA forecast result is lower than the number of existing time series patent data averages.

A Study on Random Selection of Pooling Operations for Regularization and Reduction of Cross Validation (정규화 및 교차검증 횟수 감소를 위한 무작위 풀링 연산 선택에 관한 연구)

  • Ryu, Seo-Hyeon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.4
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    • pp.161-166
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    • 2018
  • In this paper, we propose a method for the random selection of pooling operations for the regularization and reduction of cross validation in convolutional neural networks. The pooling operation in convolutional neural networks is used to reduce the size of the feature map and for its shift invariant properties. In the existing pooling method, one pooling operation is applied in each pooling layer. Because this method fixes the convolution network, the network suffers from overfitting, which means that it excessively fits the models to the training samples. In addition, to find the best combination of pooling operations to maximize the performance, cross validation must be performed. To solve these problems, we introduce the probability concept into the pooling layers. The proposed method does not select one pooling operation in each pooling layer. Instead, we randomly select one pooling operation among multiple pooling operations in each pooling region during training, and for testing purposes, we use probabilistic weighting to produce the expected output. The proposed method can be seen as a technique in which many networks are approximately averaged using a different pooling operation in each pooling region. Therefore, this method avoids the overfitting problem, as well as reducing the amount of cross validation. The experimental results show that the proposed method can achieve better generalization performance and reduce the need for cross validation.

The study on DC-link Film Capacitor in 3 Phase Inverter System for the Consideration of Frequency Response (3상 인버터 시스템에서 주파수 특성을 고려한 필름 콘덴서의 DC-link 적용 방법에 관한 연구)

  • Park, Hyun-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.4
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    • pp.117-122
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    • 2018
  • A large-capacity three-phase system air conditioner recently includes an inverter circuit to reduce power consumption. The inverter circuit uses a DC voltage that comes from DC-link power capacitor with the function of rectifying, which means AC voltage to DC voltage using a diode. An electrolytic capacitor is generally used to satisfy the voltage ripple and current ripple conditions of a DC-link power capacitor used for rectifying. Reducing the capacitance of the capacitor decreases the size, weight, and cost of the circuit. This paper proposes an algorithm to reduce the input ripple current by combining the minimum point estimation phase locked loop (PLL) phase control and the average voltage d axis current control technique. When this algorithm was used, the input ripple current decreased by almost 90%. The current ripple of the DC-link capacitor decreased due to the decrease in input ripple current. The capacitor capacity can be reduced but the electrolytic capacitor has a heat generation problem and life-time limitations because of its large equivalent series resistance (ESR). This paper proposes a method to select a film capacitor considering the current ripple at DC-link stage instead of an electrolytic capacitor. The capacitance was selected considering the voltage limitation, RMS (Root Mean Square) current capacity, and RMS current frequency analysis. A $1680{\mu}F$ electrolytic capacitor can be reduced to a $20{\mu}F$ film capacitor, which has the benefit of size, weight and cost. These results were verified by motor operation.

Analysis of Educational Needs for Career Anchor and Career Development of Nursing Students (간호대학생의 커리어앵커와 경력개발을 위한 교육요구 분석)

  • Lee, Ji-An;Park, Su-Hong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.4
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    • pp.293-300
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    • 2018
  • The purpose of this study is to investigate the educational needs for career development according to the job type of nursing college students. In order to achieve the purpose of the study, 146 nursing college students from K and P universities in the Busan and Kyungnam areas were analyzed using a career anchor questionnaire. In addition, 28 nursing college students who showed a higher level of tendency among job types were selected and divided into 4 teams, and a focus group interview was conducted based on the contents of the created map. Its purpose is to investigate the educational needs of nursing college students to enhance their career development. First, the career anchor types of the nursing college students showed the highest score in the areas of lifestyle, security and stability, while the lowest types of career anchor were pure challenge and general managerial competence. Second, the educational needs for career development were categorized into four areas, namely major competence, practical competence, personality competence, and resource management competence. The major competences are nursing expertise and skills. The practical competences consisted of ward task management, communication, crisis coping ability and personality competence and these were divided into cooperation and responsibility recognition. The resource management competence consists of time management ability and stress management ability. The results of this study are meaningful in that they can be used as the basic educational data for the career development of nursing college students in the future. In addition, it is expected that they can be applied to the development of a curriculum for the improvement of nursing practice.

The Effects of the Elements of Cash Flow and Accrual on the Consistency of Cash Flow and on the Firm's Value (현금흐름과 발생액 및 구성요소들이 현금흐름의 지속성과 기업가치에 미치는 영향)

  • Park, Chang-Rae;Lee, Sang-Hee
    • Korean Business Review
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    • v.22 no.2
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    • pp.61-86
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    • 2009
  • The purpose of this article is to investigate the effects of cash flow and accrual, which are the elements of earnings, and those of the elements of cash flow and accrual on the consistency of cash flow and firm's value. We analyzed 4 kinds of regression models, of which the independent variables are this period's cash flow, the elements of cash flow, accrual, and the elements of accrual, and the dependent variables are the next period's cash flow, and the stock price at the end of financial statements disclosure months, respectively. The sample firms were the manufacturing companies listed on the Stock Exchange 1980 through 2006, of which the fiscal year ended in December. And, the results of the analyses are as follows: Cash flow and accrual are shown to have significant relationships with cash flow consistency and the evaluations of firms' value. And, the elements of cash flow or accrual proved to have more influence than the total amount of them, on cash flow consistency and the evaluation of firms' value. Also, the results present that some of the elements of cash flow and accrual differently affect cash flow consistency and the evaluation of firms' value. Accordingly, this study indicates that each of the elements of cash flow and accrual needs to be considered respectively rather than the total amount of them, in the case that cash flow and accrual are used in the decision-making concerned with the forecast of cash flow and the evaluation of firms' value. This study also shows that each element of cash flow and accrual needs to be used differently for cash flow forecast and the evaluation of firms' value.

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Using the Balanced Scorecard and Organizational Performance (조직의 경영성과 측정과 평가를 위한 균형성과표(BSC) 모형의 도입 및 활용 효과에 관한 연구)

  • Jang, Chung-Seok
    • Korean Business Review
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    • v.22 no.1
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    • pp.77-101
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    • 2009
  • The main purpose of this study is to assess the effect of using Balanced Scorecard, and relationship among learning and growth performance, internal business performance, customer performance, financial performance, and business performance. To achieve this study, theoretical and empirical studies related to Balanced Scorecard were carried out simultaneously. A field survey was undertaken through questionnaire sampling a population of construction firms. The established hypotheses related to Balanced Scorecard and organizational performance were verified by the paired-t test analysis using SPSS. The result of this research are as follows : First, BSC firm's learning and growth performance are higher than those of before BSC adopting firms significantly. Second, BSC firm's internal business performance level is higher than that of before BSC firm's significantly. Third, BSC firm's customer performance level is higher than that of before BSC firm's significantly. Fourth, BSC firm's financial performance level is higher than that of before BSC firm's significantly. Fifth, BSC firm's Business performance level is higher than that of before BSC firm's significantly. This study contributes to the BSC research by being the study focus on the BSC at the general indicators and provides evidence that may help understanding the possible relationship between BSC adoption and improvement of organizational performance. There are some limitations, however, of this study. The result are based on a cross sectional sample of construction firms, which may not be reflective of the entire population.

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Path Analysis of Geometric Psychology type, Positive Psychological Capital, and Communication Competence for University Students (대학생의 도형심리 유형, 긍정심리자본, 의사소통능력 간의 경로분석)

  • Kim, Myoung-Sook;SEO, Ho-Chan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.6
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    • pp.355-364
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    • 2018
  • The objective of this study is to conduct basic research for the development of programs for improving university students' communication competence. As such, it seeks to determine if positive psychological capital can mediate the relationship between the geometric psychology type and communication competence. To that end, 321 Korean university students were surveyed using a questionnaire, and the data underwent scale reliability analysis, regression analysis, and path analysis. Regression analysis revealed the consistent regression results of variables, including geometric psychology type, positive psychological capital, and communication competence. Path analysis confirmed that positive psychological capital mediated the relationship between the geometric psychology type and communication competence, and the results suggested different patterns according to type of geometric psychology. The circle type mediated the sub-variable resilience vis-a-vis communication competence, and directly influenced the latter. The triangle type mediated the sub-factors of positive psychological capital - self-efficacy and resilience -vis-a-vis communication competence, and thus influencing the latter. The square type mediated the sub-factor of positive psychological capital - self-efficacy - vis-a-vis communication competence, and directly influenced the latter. The S type did not mediate positive psychological capital vis-a-vis communication competence, but directly influenced the latter. Thus, considering the above findings, in order to develop university students communication improvement programs, programs should be developed with the application of positive psychological capital considering geometric psychology type.