• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제33회 춘계학술대회 개최
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• pp.201-211
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• 2001

The influence of aerated oil on high-speed journal bearing is examined by classical thermohydrodynamic lubrication theory coupled with analytical models for viscosity and density of aerated oil in fluid-film bearing. Convection to the walls, mixing with supply oil and re-circulating oil, and some degree of journal misalignment are considered. The considered Parameters for the study of bubbly lubrication are oil aeration level, air bubble size, shaft misalignment and shaft speed. The results show that deliberate oil aeration can more clearly bring on the increasing load capacity under high-speed operation of plain journal hearing than previous normal speed operation. And the load capacity may be increased more by oil aeration under the conditions of shaft misalignment and the increasing speed.

• 지역연구
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• 제8권1호
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• pp.1-29
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• 1992

The major purpose of this paper is to examine two closely related issues. An attempt is made here to examine internationally high land price in Korea from the perspectives of market fundamentals (MF) and bubble theory, respectively. Another theoretical issue, whether land speculation can result in market failure, is also examined. It has been concluded that the primary causes for the rapid increases in land prices in Korea, could be found in the perspective of MF. (1) The financial intermediaries has been controlled by the government since 1960s. Real Interest rates in the commercial banks has been controlled at the level of zero or sometimes negative; scarce financial resources has been rationed by the government. The governmental control of the bands has also resirained the development of securities market. Money, which can not find the appropri opportunity for saving in financial market, moves to land market. (2) Socially created land value, based on rapid economic gorwth and big public investment, has been appropriated mainly by the private: The effective tax rate of land holding tax has been under 0.02 percent; Real Estate Capital Galns Tax has, in fact, affected few persons, mainly because examptions and preferential taxation have been widely permitted. (3) The government has ploaced severe limitations on rural-to-urban land conversion, although the demand for urban uses has repidly grown. All factors above caused the cyclical land speculation. This, in turn, created the myth that land prices will inevitably continue to rise. Based on the myth, the growing bubble in land price has been created. This is the secondary reason for high land price relative to income in Korea. It is also shown that it is possible that speculation in land results in market failure because land is fixed in quantity and can be used for production and speculation purposes simultaneously.

• Journal of Information Science Theory and Practice
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• 제7권2호
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• pp.40-53
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• 2019

Although fake news has been present in human history at any time, nowadays, with social media, deceptive information has a stronger effect on society than before. This article answers two research questions, namely (1) Is the dissemination of fake news supported by machines through the automatic construction of filter bubbles, and (2) Are echo chambers of fake news manmade, and if yes, what are the information behavior patterns of those individuals reacting to fake news? We discuss the role of filter bubbles by analyzing social media's ranking and results' presentation algorithms. To understand the roles of individuals in the process of making and cultivating echo chambers, we empirically study the effects of fake news on the information behavior of the audience, while working with a case study, applying quantitative and qualitative content analysis of online comments and replies (on a blog and on Reddit). Indeed, we found hints on filter bubbles; however, they are fed by the users' information behavior and only amplify users' behavioral patterns. Reading fake news and eventually drafting a comment or a reply may be the result of users' selective exposure to information leading to a confirmation bias; i.e. users prefer news (including fake news) fitting their pre-existing opinions. However, it is not possible to explain all information behavior patterns following fake news with the theory of selective exposure, but with a variety of further individual cognitive structures, such as non-argumentative or off-topic behavior, denial, moral outrage, meta-comments, insults, satire, and creation of a new rumor.

• 대한기계학회논문집
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• 제12권3호
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• pp.590-598
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• 1988

본 연구에서는 난류유동이론을 적용하여 2차원 스크린의 후류에 관한 유동특 성을 연구하였다. 이를 위해 적합한 난류모델 및 스크린의 존재를 고려한 수치해석 방법을 연구하였다. 스크린의 저항이 커서 스크린 하류유동이 역류가 되는 경우도 포함하였다.

• 농촌계획
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• 제15권4호
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• pp.183-197
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• 2009

The management aggravation of forests and the increase in the demand on resorts promote the urban use of forests, and the development of forests-using resorts is becoming an important political issue. Based on this understanding, this paper purports to examine the causes for the failure of the Shinrin Toshi policy (development of living space and resorts) which Japan promoted, and also examined the future direction of the development of forest resorts in Korea. As a result of the study, it was found that the Shinrin Toshi policy of Japan was promoted through the new changes of bubble economy and forest culture theory, and various strategies for the co-existence of human beings and nature were worked out. However, the policy took precedence without concrete plan production, which was found as the direct cause for the failure. The reasons for not having concrete plan production were: the target and the resort lifestyle (who will use it and what life will be developed) were not clear; the subject of the policy was restricted to state forests; and the dependence on civil capital in the promotion of the policy was too big. Therefore, in order to make the Shinrin Toshi policy successful, concrete lifestyle how the forest resort will be used and operated - needs to be set up and resources should be concretized. For this, the concrete demand on the forest resort life and the traditional community property of forest areas will have to be examined.

• 공학교육연구
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• 제19권2호
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• pp.26-33
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• 2016

A camp program where the theory of inventive problem solving TRIZ is applied to real problems of the industry was developed and taught at a five-day seminar apart from the standard curriculum at a university D in Gyeonggido. This study focuses on the educational effect that the TRIZ method has on the engineering students when their creative problem solving skills are required to solve industry problems on their own with the knowledge from their courses. For five days, the students were educated about TRIZ and assigned a real industry problem "Removal of friction caused by bubble formation in water heating pipelines". By applying TRIZ to the problem, the students developed an "Air removing Air Arrester" which received the evaluation, "with understanding the system architecture and the task objective causes and formation of the problem could be handled which directly helps the company's R&D". In this case, TRIZ offers the students a guideline and knowledge on how to approach problems and as a result the students provided a practical solution. During the process, the TRIZ method instilled confidence in the students and proved to be a motivation. It becomes obvious that this short-term program has a positive effect on students' way of thinking creatively and increasing their problem-solving abilities.

• 한국정보과학회논문지:시스템및이론
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• 제33권11호
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• pp.810-819
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• 2006

본 논문에서는 네트워크 통신에서 혼잡으로 인한 패킷의 손실을 최소화하기 위하여 새로운 버퍼 모델인 적응적인 이중 버퍼 모델을 제안한다. 이는 제약된 메모리 환경에서 송수신 버퍼가 서로의 여유 공간을 공유하여 패킷의 손실을 최대한 줄일 수 있는 버퍼 모델이다. 또한 리스트와 비슷한 성능을 지니는 본 버퍼 모델은 자유 리스트를 사용한 버퍼와 달리 메모리 누수로 인한 버블(bubbles) 현상을 방지하므로 제한된 환경의 네트워크 버퍼에 적용할 수 있으며 배열을 사용하는 경우와 비교 할 때 최대 100% 성능 향상을 기대할 수 있다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1446-1451
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• 2008

The clay found in the river or in any waste water treatment plant usually have a very high content of water. A large amount of sediments hinder the navigation in river. In waste water treatment plant, there is requirement of settling the thick sludge. These problems are overcome by using rapid means of sedimentation and settling. This paper focus on how method of Electrokinetic sedimentation can be made faster. Sedimentation using Electrokinetic phenomenon has been discussed with varied voltage applied and effect and dose of coagulant in increasing the process. The experimental test has been carried out at water content that are generally present in the case of river and small canals carrying waste water. This paper also focus on different heavy metals concentration during the process and the power aspects of process. A series of experiment were done to support the proposed theory and how a bubble formation could hinder the purpose of experiment.

• Journal of Information Science Theory and Practice
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• 제10권1호
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• pp.59-72
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• 2022

This text discusses elements and characteristics of contemporary informational reality, that is, the ways of producing, circulating, organizing, using, and appropriating information in the current context. Initially, seven terms and concepts used to describe this reality are discussed: fake news, false testimonials, hate speech, scientific negationism, disinformation, post-truth, and infodemic. Next, an attempt is made to present a framework for such phenomena as an object of study in information science. Therefore, this scenario is characterized based on the three main models of information science study: physical, cognitive, and social. The contribution of each of them to the study of contemporary informational reality is analyzed, identifying aspects such as the bubble effect, clickbaits, confirmation bias, cults of amateurism, and post-truth culture. Finally, it presents the discussion of a possible veritistic turn in the field, in order to think about elements not covered so far by information science in its task and challenge of producing adequate understanding and diagnoses of current phenomena. In conclusion, it is argued that only accurate and comprehensive diagnoses of such phenomena will allow information science to develop services and systems capable of combating their harmful effects.

• Spatial Information Research
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• 제22권6호
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• pp.55-65
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• 2014

본 논문은 조경설계를 위한 창의적 개념화를 지향하는 공간 의사 결정 시스템 모델에 대한 연구이다. (1)정보의 폭발 및 무시 (2)원칙성과 융통성의 딜레마 (3)비구조화된 성격의 계획 및 설계라는 세가지 특징 때문에, 현재 정보중심의 GIS는 큰 역할을 못하고 있다. 이에 현재의 정보중심의 GIS에 대한 대안으로 공간 개념화를 지향하는 SDSS(공간의 사결정지원시스템)모델을 제시하고자 한다. 미래의 공간 개념화 지향의 SDSS는 인지적 관점을 기반으로 한 공간개념화를 현재의 GIS기술과 연계시킴으로써 조경설계의 비구조적인 문제를 효율적이고, 창조적으로 해결할 수 있다. 공간개념화 지향의 SDSS 모델은 (1)인간정보처리 (2)도구 및 이론의 상호작용 (3)인지과학 및 실천인식론 (4)의사결정지원 시스템 (5)인간과 컴퓨터의 상호작용 (6)창조적인 사고라는 핵심이론 및 기술을 반영한다. 향후 구현될 공간 개념화 지향의 SDSS는 설계자가 공간계획 및 설계상에서 "숨겨진 조직"을 파악할 수 있게 하고, 생성 및 개념화 능력을 통해 새로운 아이디어를 개발하고 이를 다른 설계자와 공유할 수 있게 한다. 공간개념화는 (1)버블다이어그램 지향의 설계지원 시스템 (2)어의적 기억의 확장으로서의 프로토타입 (3)삽화적 기억의 확장으로서 스크립트라는 세 가지 핵심 아이디어를 통해 공간 설계의 개념화를 보다 용이하게 할 수 있다. 앞으로 이 세 가지 아이디어는 계획 및 설계를 위한 GIS기술의 미래 방향을 제시할 수 있을 것이다.