• Journal of Korean Society of Coastal and Ocean Engineers
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• v.10 no.3
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• pp.125-131
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• 1998

The paper deals with the application of Boundary-Fitted Coordinate System (BFCS) to the two wave models of parabolic and hyperbolic types developed on a rectangular grid system. Since the BFCS conforms the boundaries of the region in such wary that boundary conditions or calculation process can be accurately represented, improvement in predicting the wave fields can be achieved. The numerical results show a good agreement with the analytical results for either waves propagating or reflecting along a circular channel of constant depth. Simulation of reflecting waves in a parabolic wave model is accomplished by the backward calculation as if waves approached at the cross wall take a turn in the opposite direction and propagate against a channel.

• Journal of Families and Better Life
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• v.21 no.4
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• pp.103-116
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• 2003

The purpose of this study was to examine the economic status of retired elderly households. This study especially looked for the differences in the economic status among retired elderly households and the level of subjective financial strain. The data were drawn from the data of 2000 Korean Labor and Income Panel Study (KLIPS) conducted by the Korea Labor Institute. The major findings are as follows: 1) The levels of income in the retired households were found to be lower than those of the employed elderly households, and the transfer income took the biggest portion out of 5 income types reflecting high economic dependency. 2) The levels of expenditure were found to be similar to the minimum living cost, and the food cost at home was 41.9% of the expenditure. 3) About 40% and 27.3% of households reported that they felt financial strain due to food expenditures at home and health care respectively. 4) Ninety percent of all assets were found to be real estate, reflecting the lack of asset liquidity. Further, retired elderly households were classified as 'not at all strained financially', 'moderate', 'seriously strained', and 'extremely strained' groups according to their subjective assessment. The last two groups showed the lower level of income and expenditures than the first two groups. In particular, 26.5% of retired elderly households belonged to 'extremely strained' group and showed very serious economic problems.

• KIEAE Journal
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• v.10 no.1
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• pp.57-64
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• 2010

Electric energy is indispensible of the development of the industrial and living sector. Among the energy sectors, the building area shares 20% of the produced electric power in Korea. As we plan to supply the apartment, we need to forecast the required amount of the electric energy and supply the infrastructure to apartment for the lighting, cooling. Nonetheless, it is not easy to forecast the required amount of the electric energy, considering the management aspect, building physical aspect and social-geographic aspect. In this paper, it studied the estimation model of the electric energy, reflecting the affecting variables such as total area, number of household, geography and so on. The estimation model is proposed in 3-types which explained in central heating, individual heating and district heating, and each type have two estimation model, reflecting the affecting variable and corelation between variables to eliminate the muticolinearity. The unit of electric energy consumption per area and year is similar in three heating type and the results are as follows; the central heating is $34.446kWh/yr{\cdot}m^2$, individual type is $35.756446kWh/yr{\cdot}m^2$ and district heating is $34.285446kWh/yr{\cdot}m^2$.

• Human Ecology Research
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• v.56 no.3
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• pp.301-315
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• 2018

This study explores the critical reflection process experienced by home economics preservice teachers during practicum. Data were collected in a critical analysis of class, practicum review, and journals written by sixteen preservice teachers. Text material were composed of 188 transcripts on A4 paper and 36 page of mini-notes. The collected data were analyzed by a thematic coding method in qualitative research and proceeded in the order of three steps of transference, coding, and subject discovery. The emerging themes were: 1) Observing class 2) Practicing class 3) Growth of class practice 4) Reflecting class. First, the observing class was an exploration process through the viewing of daily classes that involved the process of recognizing the classroom situation and various classroom contexts. Second, the practicing class was to strengthen the consideration of the class to form a relationship that could lead to learning in educational situations. Third, the growth of class practice was intended to recognize the orientation of the subject matter with pedagogical content knowledge. Four, the reflecting class was the process of experiencing practice with a continuous understanding of the class, class reflection, and changing the perspective from the current status. There is a part where critical reflection is difficult to be promoted deeply during 4 weeks; however, there was a possibility of a reflection practice that could promote achievement through the experience of a practicing class.

• Journal of Information Processing Systems
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• v.4 no.3
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• pp.113-120
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• 2008

Most enterprises have controlled claim data related to marketing, production, trade and delivery. They can extract the engineering information needed to the reliability of unit from the claim data, and also detect critical and latent reliability problems. Existing method which could detect abnormal quality unit lists in early stage from claim database has three problems: the exclusion of fallacy probability in claim, the false occurrence of claim fallacy alarm caused by not reflecting inventory information and too many excessive considerations of claim change factors. In this paper, we propose a process and methods extracting abnormal quality unit lists to solve three problems of existing method. Proposed one includes data extraction process for reliability measurement, the calculation method of claim fallacy alarm probability, the method for reflecting inventory time in calculating claim reliability and the method for identification of abnormal quality unit lists. This paper also shows that proposed mechanism could be effectively used after analyzing improved effects taken from automotive company's claim data adaptation for two years.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.11
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• pp.973-981
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• 2013

The main role of an acoustic diffuser is to diffuse reflected sound field spatially. Since the pioneering work of Schroeder, there have been investigations to improve its performance by using shape/sizing optimization methods. In this paper, a gradient-based topology optimization algorithm is newly presented to find the optimal distribution of reflecting materials for maximizing diffuser performance. Time-harmonic acoustic analysis in a two-dimensional acoustic domain is carried out where the domain is discretized by finite elements. Perfectly matched layers are placed to surround the domain to simulate non-reflecting boundary conditions. Design variables are assigned to each element of which material properties are interpolated between those of air and those of a rigid body. An approach to extract the reflected field from the total acoustic field is employed. To validate the effectiveness of the proposed method, design problems are solved at different frequencies. The performance of the optimized diffusers obtained by the proposed method is compared against that of the conventional Schroeder diffusers.

• Journal of Information Technology Services
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• v.18 no.3
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• pp.117-128
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• 2019

The remarkable achievements of the artificial intelligence in recent years are also raising awareness about its potential risks. Several governments and public organizations have been proposing the artificial intelligence ethics for sustainable development of artificial intelligence by minimizing potential risks. However, most existing proposals are focused on the developer-centered ethics, which is not sufficient for the comprehensive ethics required for ongoing intelligent information society. In addition, they have chosen a number of principles as the starting point of artificial intelligence ethics, so it is not easy to derive the guideline flexibly for a specific member reflecting its own situation. In this paper, we classify primitive members who need artificial intelligence ethics in intelligent information society into three : Developer, Supplier and User. We suggest a new artificial intelligence ethics, Seoul PACT, with minimal principles through publicness (P), accountability (A), controllability (C), and transparency (T). In addition, we provide 38 canonical guidelines based on these four principles, which are applicable to each primitive members. It is possible for a specific member to duplicate the roles of primitive members, so that the flexible derivation of the artificial intelligence ethics guidelines can be made according to the characteristics of the member reflecting its own situation. As an application example, in preparation for applying artificial intelligence to e-government service, we derive a full set of artificial intelligence ethics guideline from Seoul PACT, which can be adopted by the special member named Korean Government.

• Journal of the Optical Society of Korea
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• v.17 no.6
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• pp.533-537
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• 2013

Space telescope optics is one of the major parts of any space mission used to observe astronomical targets or the Earth. This kind of space mission typically involves bulky and complex opto-mechanics with a long optical tube, but attempts have been made to observe a target with a small satellite. In this paper, we describe the optical design of a reflecting telescope for use in a CubeSat mission. For this design we adopt the off-axis segmented method for astronomical observation techniques based on a Ritchey-Chr$\acute{e}$tien type telescope. The primary mirror shape is a rectangle with dimensions of $8cm{\times}8cm$, and the secondary mirror has dimensions of $2.4cm{\times}4.1cm$. The focal ratio is 3 which can yield a 0.383 degree diagonal angle in a $1280{\times}800$ CMOS color image sensor with a pixel size of $3{\mu}m{\times}3{\mu}m$. This optical design can capture a ${\sim}4km{\times}{\sim}2.3km$ area of the earth's surface at 700 km altitude operation.

• Journal of Environmental Science International
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• v.27 no.11
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• pp.1083-1094
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• 2018

In this study, we analyzed the characteristics of six waterfront users who are currently being used to select indicators for waterfront development. It can be classified into urban type, inland type and coast type according to the place where waterfront space is located. These waterfront design elements include accessibility, public activity, and waterfront characteristics. Waterfront environment involves selecting the elements for considered and examined these with resepect to the goals of the study. In terms of accessibility to most waterfronts, it is analyzed that users who are located within 30 minutes' distance of walking are most likely to use it. As shown in the satisfaction survey of this study, the unsatisfactory satisfaction of water quality and quantity was found to be low in Unam pond, and the result shows that the overall satisfaction of waterfront space is also low. In the case of Chunggye Chun, the results of the survey on weekdays showed that the office workers, such as the offices located in the surrounding area, were mainly resting places. In the case of Naesungchun, it is possible to select the indicators that can help the direction of the festival as a survey on the users during the festival period. In this study, waterfront location, purpose of use, characteristics, environment, and subdivision are presented as indicators to be considered when developing the waterfront. It is expected that the proposed indicators will be able to determine the direction of development by reflecting characteristics of users.

• Convergence Security Journal
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• v.18 no.1
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• pp.103-110
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• 2018

Modern society is increasingly demanding in many areas of big data processing technology to collect, aggregate, and analyze large amounts of data over the Internet and SNS. A typical application is to evaluate the reputation of a company or college. To measure and quantify a reputation, fair and precise data and efficient data processing are very important. For this purpose, a quantitative quotient was obtained using public data, a qualitative quotient was obtained through sentiment analysis using news articles, and a complex college reputation quotient was calculated. In this paper, a complex college reputation quotient was calculated based on the quantitative index, reflecting the sentimental reputation, and based on the proposed mixed university system. In this paper, the Complex College Reputation System(CCRS) was proposed, which produced the Complex College Reputation Quotient with an objective quantitative quotient and qualitative quotient reflecting the sentimental reputation to measure the college reputation.