• 한국컴퓨터정보학회논문지
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• 제23권9호
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• pp.43-50
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• 2018

In this paper, we propose a hexagon model-based efficient beacon frame scheduling approach for wireless sensor networks. The existing beacon frame scheduling approaches use a lot of slots and subslots for the beacon frame scheduling. Thus, the data from source nodes are not efficiently delivered to a sink node. Also in case a sink node needs to broadcast a beacon frame to the nodes in the network, delivering the beacon frame to the network nodes is not efficient as well. Thus, to solve the problem, we use a hexagon model to find the number of slots and subslots for the beacon frame scheduling. By using them for the beacon frame scheduling, the proposed approach performs better than other approaches in terms of the data transmission delay, the number of received data, the beacon transmission delay and the number of relaying the beacon frames.

• 생태와환경
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• 제55권4호
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• pp.320-329
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• 2022

Urban areas in watersheds increase the impervious surface, and agricultural areas deteriorate the water quality of rivers due to the use of fertilizers. As such, anthropogenic land use affects the type, intensity and quantity of land use and is closely related to the amount of substances and nutrients discharged to nearby streams. Riparian vegetation reduce the concentration of pollutants entering the watershed and mitigate the negative impacts of land use on rivers. This study analyzes the data through correlation analysis and regression analysis through point data measured twice a year in spring and autumn in 21 selected damaged tributary rivers within the Han River area, and then uses a structural equation model to determine the area land use. In the negative impact on water quality, the mitigation effect of riparian vegetation was estimated. As a result of the correlation analysis, the correlation between the agricultural area and water quality was stronger than that of the urban area, and the area ratio of riparian vegetation showed a negative correlation with water quality. As a result of the regression analysis, it was found that agricultural areas had a negative effect on water quality in all models, but the results were not statistically significant in the case of urban areas. As a result of the model estimated through the structural equation, BOD, COD, TN, and TP showed a mitigation effect due to the accumulation effect of river water quality through riparian vegetation in agricultural areas, but the effect of riparian vegetation through riparian vegetation was found in urban areas. There was no These results were interpreted as having a fairly low distribution rate in urban areas, and in the case of the study area, there was no impact due to riparian forests due to the form of scattered and distributed settlements rather than high-density urbanized areas. The results of this study were judged to be unreasonable to generalize by analyzing the rivers where most of the agricultural areas are distributed, and a follow-up to establish a structural equation model by expanding the watershed variables in urban areas and encompassing the variables of various factors affecting water quality research is required.

• 한국콘텐츠학회논문지
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• 제13권11호
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• pp.877-884
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• 2013

클라우드 컴퓨팅 서비스는 세계적으로 빠르게 성장하고 있으며, 중국에서도 바이두를 중심으로 개인용 클라우드 컴퓨팅 서비스가 비약적으로 발전하고 있다. 새로운 서비스가 등장하는 경우 서비스 수용 요인이 무엇인지에 대한 연구는 매우 중요하게 다루어지고 있다. 본 논문에서는 중국의 개인용 클라우드 컴퓨팅 서비스 사용자를 대상으로 개인용 클라우드 컴퓨팅 서비스 수용에 영향을 주는 요인을 분석하고자 한다. 이를 위해 기술수용모형을 토대로 프라이버시, 정보활용 욕구, 서비스 유형, 서비스 적절성, 시스템 품질, 시스템 보안 등의 연구변수를 포함하여 확장한 연구모형을 설계하였고, 설계한 연구모형은 구조방정식모형을 사용하여 실증하였다. 검증결과에 의하면, 프라이버시, 서비스 적절성, 시스템 품질, 시스템 보안 등의 요인은 유용성과 사용용이성에 영향을 주며 결국에는 서비스 수용의도에 긍정적인 영향을 미치는 것으로 나타났다. 반면, 정보활용 욕구와 서비스 유형은 유용성과 사용용이성 모두에 유의한 영향을 미치지 않는 것을 확인할 수 있다.

• 한국정보과학회논문지:소프트웨어및응용
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• 제29권4호
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• pp.211-224
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• 2002

소프트웨어 시스템이 대형화되고 복잡화해 짐에 따라 사용자의 요구사항을 올바로 분석하고 서술하는 것이 중요시되고 있다. 이중 유스케이스 분석 방법은 요구사항 분석에서의 복잡도를 해결해 주는 장점 때문에, 객체지향의 분석 설계와 컴포넌트 기반의 개발에서 많이 이용되고 있다. 그러나 이러한 유스케이스 분석 방법은 흩어진 유스케이스들의 단순한 집합이어서 유스케이스들을 구조화하기 어렵고, 유스케이스들간의 영향분석을 하기 어려우며, 비 기능적인 요구사항을 표현하기 어렵다. 이러한 문제를 해결하기 위해서, 본 논문에서는 목표지향의 분석 방법을 이용한 유스케이스 모델에의 적용방안을 제안하였다. 현재 연구되고 있는 목표지향의 분석은 요구사항으로부터 목표를 추출하기 어렵고, 분석 방법이 분석가의 경험적 근거에 의존적이다. 따라서 본 논문에서는 요구사항으로부터 목표를 직관적으로 식별하는 것이 어렵기 때문에 기초자료로 시나리오를 이용하여 그것으로부터 목표를 추출하는 시나리오 근간의 목표지향 분석 방법을 제안했다. 마지막으로 제안된 방안을 검증하기 위해 ITS의 시내버스정보 서브시스템에 적용하였다. 이 제안된 방안을 통해서 소프트웨어 분석가들은 유스케이스들간의 영향분석을 쉽게 하여 소프트웨어 개발초기에 유스케이스들간의 불일치(inconsistency)를 찾을 수 있고, 비기능적인 요구사항을 표현할 수 있다.

• 전기학회논문지
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• 제65권6호
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• pp.979-986
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• 2016

At present, electric power industry around the world are being gradually changed to a new paradigm, such as electrical energy storage system, the wireless power transmission. Demand for ESS, the core technology of the new paradigm, has been growing worldwide. However, it is essential to estimate the optimal capacity of ESS facilities for frequency regulation because the benefit would be saturated in accordance with the investment moment and the increase of total invested capacity of ESS facilities. Hence, in this paper, the annual optimal mathematical investment model is proposed to estimate the optimal capacity and to establish investment plan of ESS facility for frequency regulation. The optimal mathematical investment model is newly established for each season, because the construction period is short and the operation effect for the load by seasons is different unlike previous the mathematical investment model. Additionally, the marginal operating cost is found by new mathematical operation model considering no-load cost and start-up cost as step functions improving the previous mathematical operation model. ESS optimal capacity is established by use value in use iterative methods. In this case, ESS facilities cost is used in terms of the value of the beginning of the year.

• 한국농공학회지
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• 제40권1호
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• pp.68-77
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• 1998

The purpose of this paper is to establish a method estimating the daily urban water demand using statistical analysis that is used for developing the efficient management and operation of the water supply facilities, and accurary of the model is verified by error rate and F-value. The data used in this study were the daily urban water use, the weather conditions such as temperature, precipitation, relative humidity, etc, and the day of The week. The case study was taken placed for the city of Namwon in Korea. The raw data used in this study were rearranged either by month or by season for analysis purpose, and the statistical analysis was applied to the data to obtain the regression model As a result of this study, the linear regression model was developed to estimate the daily urban water use with weather condition. The regression constant and coefficients of the model were determined for each month of a year. The accuracy of the model was within 3% of average error and within 11% of maximum error. The resulting model was found to he useful to the practical operation and management of the water supply facilities.

• Earthquakes and Structures
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• 제8권4호
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• pp.935-956
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• 2015

Structural Health Monitoring (SHM) of steel towers has become a hot research topic. From the literature, it is impractical and impossible to develop a "general" method that can detect all kinds of damages for all types of structures. A practical method should make use of the characteristics of the type of structures and the kind of damages. This paper reports a feasibility study on the use of measured modal parameters for the detection of damaged braces of tower structures following the Bayesian probabilistic approach. A substructure-based structural model-updating scheme, which groups different parts of the target structure systematically and is specially designed for tower structures, is developed to identify the stiffness distributions of the target structure under the undamaged and possibly damaged conditions. By comparing the identified stiffness distributions, the damage locations and the corresponding damage extents can be detected. By following the Bayesian theory, the probability model of the uncertain parameters is derived. The most probable model of the steel tower can be obtained by maximizing the probability density function (PDF) of the model parameters. Experimental case studies were employed to verify the proposed method. The contributions of this paper are not only on the proposal of the substructure-based Bayesian model updating method but also on the verification of the proposed methodology through measured data from a scale model of transmission tower under laboratory conditions.

• 대기
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• 제32권2호
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• pp.103-118
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• 2022

This study evaluates the simulated meteorological fields with a particular focus on the low-level wind, which plays an important role in air pollutants dispersion, under the varying synoptic environment. Additionally, the effects of subgrid-scale orography parameterization and improved topography/land-use data on the simulated low-level wind is investigated. The WRF model version 4.1.3 is utilized to simulate two cases that were affected by different synoptic environments. One case from 2 to 6 April 2012 presents the substantial low-level wind speed over the Korean peninsula where the synoptic environment is characterized by the baroclinic instability. The other case from 14 to 18 April 2012 presents the relatively weak low-level wind speed and distinct diurnal cycle of low-level meteorological fields. The control simulations of both cases represent the systematic overestimation of the low-level wind speed. The positive bias for the case under the baroclinic instability is considerably alleviated by applying the subgrid-scale orography parameterization. However, the improvement of wind speed for the other case showing relatively weak low-level wind speed is not significant. Applying the high-resolution topography and land-use data also improves the simulated wind speed by reducing the positive bias. Our analysis shows that the increased roughness length in the high-resolution topography and land-use data is the key contributor that reduces the simulated wind speed. The simulated wind direction is also improved with the high-resolution data for both cases. Overall, our study indicates that wind forecasts can be improved through the application of the subgrid-scale orography parameterization and high-resolution topography/land-use data.

• Journal of Information Technology Applications and Management
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• 제26권6호
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• pp.29-46
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• 2019

This study analyzed the factors influencing the technology acceptance of the general public in the drones and ARs, one of the key technologies of the industry 4.0. The theoretical basis was the extended unified theory of acceptance and use of technology model(UTAUT2), which uses performance expectancy, effort expectancy, social influence, facilitating conditions, and hedonic motivation as factors common to both services. The price value factor was excluded considering that most ARs were free, and the perceived risk factors, including privacy, which were not in UTAUT2, were included because they are important factors for ICT technology acceptance. The hypothesis was tested by structure equation model. Social influence and hedonic motivation had a positive(+) effect on intention to use technology. On the other hand, in the case of effort expectancy, neither the AR nor the drone had a significant influence on intention to use technology. Furthermore, performance expectancy had a positive(+) effect on intention to use in AR, but no significant influence was found out in drones. On the contrary, in the case of the facilitating conditions, the influence of the drones was positive (+), but the relation of AR was not investigated. The perceived risk was tested for the negative (-) influence of use intention of AR, but no significant relationship was found out for the drones. Among the significant influencing factors, hedonic motivation was the most powerful factor in AR and drones. Theoretical and practical implications are presented based on these results.

• 품질경영학회지
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• 제29권3호
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• pp.124-137
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• 2001

In general, it is very efficient and effective to use screening variables that are correlated with the performance variable in case that measuring the performance variable is impossible (destructive) or expensive. The general methodology for searching surrogate variables is regression analysis. This paper considers the inspection problem in CRT (Cathode Ray Tube) production line, in which the performance variable (dependent variable) is binary type and screening variables are continuous. The general regression with dummy variable, discriminant analysis and binary logistic regression are considered. The cost model is also formulated to determine economically inspection procedure with screening variables.