• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.38 no.3
• /
• pp.271-277
• /
• 2014

Internal structures, especially those located in the upstream of a reactor core, may have a significant influence on the core inlet flow rate distribution depending on both their shapes and the relative distance between the internal structures and the core inlet. In this study, to examine the effect of the reactor internal structure geometry treatment method on the prediction accuracy for the scale-down APR+ flow distribution, simulations with real geometry modeling were conducted using ANSYS CFX R.14, a commercial computational fluid dynamics software, and the predicted results were compared with those of the porous medium assumption. It was concluded that the core inlet flow distribution could be predicted more accurately by considering the real geometry of the internal structures located in the upstream of the core inlet. Therefore, if sufficient computational resources are available, an exact representation of these internal structures, for example, lower support structure bottom plate and ICI nozzle support plate, is needed for the accurate simulation of the reactor internal flow.

• Informatization Policy
• /
• v.24 no.2
• /
• pp.87-104
• /
• 2017

The Fourth Industrial Revolution, which is based on the development of information and communication technology (ICT), is expected to replace human knowledge work, which will cause problems of mass unemployment and wide income gap from job polarization. Furthermore, the change is expected to be rapid and wide, demanding proactive measures to respond to such abrupt social changes. However, previous literatures assume that the traditional form of employment will continue and provide limited solutions only. On the other hand, the Fourth Industrial Revolution will enable transition to the Prosumer Economy, which will ultimately lead consumers to become producers through increased job flexibility. If the prosumer economy arrives and the consumers become producers, it will no longer be the matter of finding workplace but rather, the matter of finding the work itself. In this regard, the new technologies of the Fourth Industrial Revolution can be the fundamental solution to such job issues. This paper suggests stable transition to the Prosumer Economy in order to solve the job issues in the age of the Fourth Industrial Revolution. In order to effectively support the process, this paper suggests first, ensuring the amount of education by shortening labor time; second, facilitating life-time education through free online education service; and third, closing the digital divide through mandatory use of the e-government system.

• Economic and Environmental Geology
• /
• v.36 no.3
• /
• pp.213-223
• /
• 2003

We estimated the Moho depth of Korean Peninsula from gravity anomalies and digital elevation model. The satellite radar altimetry-derived global free-air gravity model was used to ensure the homogeneity in both data and frequency domains of the original data. Two different methods were implemented to calculate the Moho depth; the wavenumber correlation analysis (Kim et al., 2000a) and the power spectrum analysis. The former method calculates depth-to-the-Moho by correlating topographic gravity effect with free-air gravity anomaly in the wavenumber domain under the assumption that the study area is not isostatically compensated. The latter one, on the other hand, considers the different density layers (i.e., Conrad and Moho), using complete Bouguer gravity anomaly in the Frequency domain of the Fourier transform. The correlation coefficient of the two Moho model is 0.53, and methodology and numerical error are mainly responsible for any mismatch between the two models. In order to integrate the two independentely-estimated models, we applied least-squares adjustment using the differenced depth. The resultant model has mean and standard deviation Moho depths of 32.0 km and 2.5 km with (min, max) depths of (20.3, 36.6) kms. Although this result does not include any topographic gravity effect, however, the validity of isostasy and the role of local stress field in the study area should be further studied.

• Environmental and Resource Economics Review
• /
• v.23 no.3
• /
• pp.515-551
• /
• 2014

Recently, there has been a debate as to whether bioethanol should replace some portion of gasoline for fuels in South Korea, as energy security as well as climate change issues are rising as a significant national agenda. However, a considerable amount of subsidy will be required to compensate for the higher price of bioethanol-blended gasoline. In this context, government subsidy will obtain justification only when the positive social gains from consuming bioethanol for fuels can exceed the negative social costs. Through a nation-wide choice experimental survey, we examine if South Koreans have a positive value as well as non-linear preferences on substituting bioethanol for gasoline. The results reveal that the willingness to pay for purely domestic bioethanol-blended gasoline within 10% is about 52 KRW; Koreans have concave preferences on the blending ratio of bioethanol to gasoline. The turning point of the blending ratio of bioethanol was 6.5%. Also, we found inverse U-shaped curve between income and bioethanol choice probability and the turning point of the income was calculated as 250~299million KRW. Politically conservative propensity advocates uses of bioethanol blended gasoline, but awareness on bioethanol or more weights on environmental conservation have significantly negative effects on the choice of bioethanol. However, the design of the survey questionnaire is incompatible with the RFS of Korea and assumes orthogonality among the following four interrelated attributes: (i) domestic or offshore procurement of feedstocks in the case of domestic production, (ii) domestic production or import of bioethanol, (iii) the blending ratios, and (iv) the retail price increases. In addition, the results of model estimation and of model selection test are not definite. Hence, the results in this study should not be directly applied to the design of the specifics of the Korean RFS. Hence, the results in this study require cautions in applying to the design of the Korean RFS policy.

• Environmental and Resource Economics Review
• /
• v.16 no.1
• /
• pp.27-63
• /
• 2007

Using the CGE model, this paper investigates economic impacts of a shortage in crude oil resulting from voluntary export restraints, OPEC's agreement of a cut in oil production, and/or a storing on speculation. Unlike most previous studies considering oil price as the unpredictable variable, this study constructs the model to determine the oil price endogenously under the condition of an insufficient supply of crude oil. According to IEA's extraordinary steps for a shortage of crude oil, we investigate an economic impact of 7~12% shortage below the level of business as usual. The results show that oil price soars by 17.3~33.5%, the rate of economic growth falls by 0.52~0.96%p, and the consumer price index(CPI) rises by 0.8~1.51%p. These results imply that increasing in 1%p of oil price results in decreasing in 0.03%p of economic growth and increasing in 0.045%p of consumer price index. The production of electricity declines because of the increase in production cost. A shortage of crude oil has an effect on sources of electricity. Most reduction in electricity generation occurs from the reduction in the thermal power generation which is highly dependent on crude oil. The shortage of crude oil causes demand for petroleum to significantly decline but demand for coal and heat to increase because of the substitution effect with petroleum. Demand for gas rise in the first year but falls from the second year.

• Journal of Family Resource Management and Policy Review
• /
• v.27 no.4
• /
• pp.49-62
• /
• 2023

In order to create an organizational culture that prevents women's career breaks and promotes economic activities, this study aimed at developing educational content for workplace culture improvement for both male and female workers working at small and medium-sized enterprises in Jeollanam-do. The core content composition and content design specifically consider the characteristics of Jeollanam-do based on an advisory meeting of the field experts and researchers to ensure the on-site utilization of the content and the validity and consistency of the teaching content. The educational content is divided into three areas: understanding, effectiveness, and the implementation of a gender-sensitive work-life balance organizational culture. The aim of the content is for all employees to understand the meaning of work-life balance and to improve the organizational culture of their company from the perspective of individuals, families, companies, and society. In particular, the intention was to personally identify and implement measures to improve a gender-equal work-life balance, not only at work, but also with regard to domestic labor and leisure time. Furthermore, the content is presented from a gender-sensitive perspective that encompasses diversity, systems, and programs targeting women, men, single people, married people, young people, the elderly, and people with disabilities - all these groups are explained as examples. The content emphasizes that we should all actively participate in improving the organizational culture of our companies. In addition, the Women's New Work Center should seek ways to increase the motivation for the voluntary participation by companies and strengthen the expertise of instructors in work-life balance education.

• Journal of Intelligence and Information Systems
• /
• v.18 no.4
• /
• pp.43-57
• /
• 2012

To enhance the competitive advantage in a constantly changing business environment, an enterprise management must make the right decision in many business activities based on both internal and external information. Thus, providing accurate information plays a prominent role in management's decision making. Intuitively, historical data can provide a feasible estimate through the forecasting models. Therefore, if the service department can estimate the service quantity for the next period, the service department can then effectively control the inventory of service related resources such as human, parts, and other facilities. In addition, the production department can make load map for improving its product quality. Therefore, obtaining an accurate service forecast most likely appears to be critical to manufacturing companies. Numerous investigations addressing this problem have generally employed statistical methods, such as regression or autoregressive and moving average simulation. However, these methods are only efficient for data with are seasonal or cyclical. If the data are influenced by the special characteristics of product, they are not feasible. In our research, we propose a forecasting framework that predicts service demand of manufacturing organization by combining Case-based reasoning (CBR) and leveraging an unsupervised artificial neural network based clustering analysis (i.e., Self-Organizing Maps; SOM). We believe that this is one of the first attempts at applying unsupervised artificial neural network-based machine-learning techniques in the service forecasting domain. Our proposed approach has several appealing features : (1) We applied CBR and SOM in a new forecasting domain such as service demand forecasting. (2) We proposed our combined approach between CBR and SOM in order to overcome limitations of traditional statistical forecasting methods and We have developed a service forecasting tool based on the proposed approach using an unsupervised artificial neural network and Case-based reasoning. In this research, we conducted an empirical study on a real digital TV manufacturer (i.e., Company A). In addition, we have empirically evaluated the proposed approach and tool using real sales and service related data from digital TV manufacturer. In our empirical experiments, we intend to explore the performance of our proposed service forecasting framework when compared to the performances predicted by other two service forecasting methods; one is traditional CBR based forecasting model and the other is the existing service forecasting model used by Company A. We ran each service forecasting 144 times; each time, input data were randomly sampled for each service forecasting framework. To evaluate accuracy of forecasting results, we used Mean Absolute Percentage Error (MAPE) as primary performance measure in our experiments. We conducted one-way ANOVA test with the 144 measurements of MAPE for three different service forecasting approaches. For example, the F-ratio of MAPE for three different service forecasting approaches is 67.25 and the p-value is 0.000. This means that the difference between the MAPE of the three different service forecasting approaches is significant at the level of 0.000. Since there is a significant difference among the different service forecasting approaches, we conducted Tukey's HSD post hoc test to determine exactly which means of MAPE are significantly different from which other ones. In terms of MAPE, Tukey's HSD post hoc test grouped the three different service forecasting approaches into three different subsets in the following order: our proposed approach > traditional CBR-based service forecasting approach > the existing forecasting approach used by Company A. Consequently, our empirical experiments show that our proposed approach outperformed the traditional CBR based forecasting model and the existing service forecasting model used by Company A. The rest of this paper is organized as follows. Section 2 provides some research background information such as summary of CBR and SOM. Section 3 presents a hybrid service forecasting framework based on Case-based Reasoning and Self-Organizing Maps, while the empirical evaluation results are summarized in Section 4. Conclusion and future research directions are finally discussed in Section 5.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.774-779
• /
• 2007

IDF 곡선은 전통적으로 지점에서의 과거 관측 강우량 시계열 자료를 수집하여 작성하여 왔으며, 이때 과거 강우량 자료는 정상성을 지니고 있고 미래를 대변한다는 가정을 전제로 한다. 그러나 이미 많은 연구자들에 의해 기후변화가 전구적으로 발생하고 있으며 우리나라에서도 더 이상 기후변화의 사실여부는 이제 더이상 논란 꺼리가 아니다. 특히, 기후변화의 영향을 직접적으로 받을 수밖에 없는 수자원 분야에서는 1990년대부터 잦은 홍수와 가뭄의 반복으로 곤란을 겪고 있다. 특히, 우리나라는 협소한 국토면적과 과다한 인구로 토지나 수자원 등 국토자원 이용의 강도가 다른 나라에 비하여 현저하게 높기 때문에 지구온난화에 따른 기후변화와 같은 약간의 기후변동으로도 심각한 문제가 발생할 가능성이 내포되어 있다. 특히, 기후변화는 유역 규모의 강우 발생 패턴과 강우량의 증가 및 감소에 영향을 미치게 되며 이로 인해 강우 시계열 자료는 비정상성과 경향성을 지니게 된다. 그러나 지금까지는 IDF 곡선의 작성시 강우의 경향성을 무시해 왔다. 본 연구에서는 기후변화가 IDF 곡선에 미치는 영향을 분석하기 위하여 GCM 기후변화 시나리오를 이용하여 IDF 곡선을 작성하였다. 이를 위하여 먼저, YONU CGCM의 제한실험과 점증실험을 실시하여 전구적 규모의 기후변화 시나리오를 작성하였으며, 통계학적 축소기법과 추계학적 일기발생기법을 이용하여 대상지점의 일 수문기상 시계열을 모의하였다. 그리고 BLRP(Bartlett Lewis Rectangular Pulse) 모형과 분해(koutsoyiannis, 2000) 기법을 이용하여 모의된 일 강우 자료를 시자료로 분해하였으며 이를 이용하여 IDF 곡선을 작성하였다. 그 결과, 기후변화 시 지속기간별 재현기간별 강우량이 현재에 크게 비해 증가됨을 확인할 수 있었다.으며 여러명이 동시에 서버에 접속을 하기 때문에 컴퓨터에 부하가 많이 걸리는 모델링이나 복잡한 분석은 실시하기 어려우며, 대용량 데이터를 전송할 수 있는 대역폭이 확보 되어야 한다. 또한, Internet 환경으로 개발을 해야되기 때문에 데스크탑용 GIS에 비해 개발속도가 느리며 개발 초기비용이 많이 들게 된다. 하지만, 네트워크 기술의 발달과 모바일과의 연계 등으로 이러한 약점을 극복할 수 있을 것으로 판단된다. 따라서 본 논문에서는 인터넷 GIS를 이용하여 홍수재해 정보를 검색, 처리, 분석, 예경보할 수 있는 홍수방재정보 시스템을 구축토록 하였다.비해 초음파 감시하 치골상부 방광천자가 정확하고 안전한 채뇨법으로 권장되어야 한다고 생각한다.應裝置) 및 운용(運用)에 별다른 어려움이 없고, 내열성(耐熱性)이 강(强)하므로 쉬운 조건하(條件下)에서 경제적(經濟的)으로 공업적(工業的) 이용(利用)에 유리(有利)하다고 판단(判斷)되어진다.reatinine은 함량이 적었다. 관능검사결과(官能檢査結果) 자가소화(自家消化)시킨 크릴간장은 효소(酵素)처리한 것이나 재래식 콩간장에 비하여 품질 면에서 손색이 없고 저장성(貯藏性)이 좋은 크릴간장을 제조(製造)할 수 있다는 결론을 얻었다.이 있음을 확인할 수 있었다.에 착안하여 침전시 슬러지층과 상등액의 온도차를 측정하여 대사열량의 발생량을 측정하고 슬러지의 활성을 측정할 수 있는 방법을 개발하였다.enin과 Rhaponticin의 작용(作用)에 의(依)한 것이며, 이는 한의학(韓醫學) 방제(方劑) 원리(原理)인 군신좌사(君臣佐使) 이론(理論)에서 군약(君藥)이 주증(主症)에 주(主)로 작용(作用)하는 약물(藥物)이라는 것을 밝혀주는 것이라고 사료(思料)된다.일전 $13.447\;{\mu}g/hr/g$, 섭취 7일중 $8.123

• Journal of Korean Society of Forest Science
• /
• v.104 no.1
• /
• pp.117-126
• /
• 2015

Forest statistics of local administrative districts have many social needs, nevertheless we have some difficulties for working out an accurate statistics because of insufficient data in small-area level. Thus, new small-area estimation method has to set aside additional data, decrease errors of statistics and consider the local forest characteristics at the same time. In this study, we researched the spatial divisions that can set aside additional data for statistics production and satisfy the major premise, which is "forest characteristics of spatial divisions have to be equal to that of small-area". And we compared synthetic estimation methods based on three different spatial divisions(provinces, neighbor districts and new expanded districts). New expanded districts were divided based on the criteria of climate, soil type and tree species composition that affects local forest characteristics. Small-area statistics were assessed in terms of the ability to estimate local forest characteristics and consistency within large-area statistics. As a result, new expanded districts synthetic estimation was assessed to calculate statistics that reflects local forest characteristics better than other two estimation methods. Moreover, this synthetic estimation method produced the statistics that was included within 95% confidence interval of large-area statistics and was the closer to large-area statistics than the neighbor districts synthetic estimation.

• Journal of Korea Game Society
• /
• v.4 no.4
• /
• pp.11-18
• /
• 2004

The on-line games in the past were played by only two persons exchanging data based on one-to-one connections, whereas recent ones (e.g. MMORPG: Massively Multi-player Online Role-playings Game) enable tens of thousands of people to be connected simultaneously. Specifically, Korea has established an excellent network infrastructure that can't be found anywhere in the world. Almost every household has a high-speed Internet access. What made this possible was, in part, high density of population that has accelerated the formation of good Internet infrastructure. However, this rapid increase in the use of on-line games may lead to surging traffics exceeding the limited Internet communication capacity so that the connection to the games is unstable or the server fails. expanding the servers though this measure is very costly could solve this problem. To deal with this problem, the present study proposes the load distribution technology that connects in the form of local clustering the game servers divided by their contents used in each on-line game reduces the loads of specific servers using the load balancer, and enhances performance of sewer for their efficient operation. In this paper, a cluster system is proposed where each Game server in the system has different contents service and loads are distributed efficiently using the game server resource information such as CPU utilization. Game sewers having different contents are mutually connected and managed with a network file system to maintain information consistency required to support resource information updates, deletions, and additions. Simulation studies show that our method performs better than other traditional methods. In terms of response time, our method shows shorter latency than RR (Round Robin) and LC (Least Connection) by about 12%, 10% respectively.