• 한국멀티미디어학회논문지
• /
• 제21권3호
• /
• pp.369-381
• /
• 2018

Nowadays a personalization algorithm is gaining huge attention. It gives users selective information which is helpful and interesting in a deluge of information based on their past behavior on the internet. However there is also a fatal side effect that the user can only get restricted information on restricted topics selected by the algorithm. Basically, the personalization algorithm makes users have a narrower perspective and even stronger bias because users have less chances to get views of opponent. Eli Pariser called this problem the 'filter bubble' in his book. It is important to understand exactly what a filter bubble is to solve the problem. Therefore, this paper shows how much Google's personalized search algorithm influences search result through an experiment with deep neural networks acting like users. At the beginning of the experiment, two Google accounts are newly created, not to be influenced by the Google's personalized search algorithm. Then the two pure accounts get politically biased by two methods. We periodically calculate the numerical score depending on the character of links and it shows how biased the account is. In conclusion, this paper shows the formation process of filter bubble by a personalization algorithm through the experiment.

• 한국재료학회지
• /
• 제32권4호
• /
• pp.223-229
• /
• 2022

A porous photocatalyst concrete filter was successfully produced to remove NOx, by mixing TiO₂ photocatalyst with lightweight aerated concrete. Ultra Fine Bubbles were used to form continuous pores inside the porous photocatalytic concrete filter, which was mixed via a bubble generation experiment. The optimal mixing condition was determined to be with 4 % of the bubble generation agent B. NO removal specimens were prepared for various photocatalytic loading conditions, and the specimen containing 3 % P-25 removed NO at a concentration of 1.03 µmol in 1 h. The NO removal rate of the porous photocatalytic concrete filter prepared in this study was 10.99 %. This photocatalytic filter performance was more than 9 times the amount of NO removed by a general photocatalytic filter. The porous photocatalyst concrete filter for removing NOx developed in this study can be applied to various construction sites and the air quality can be solved by reducing NOx contributing to the formation of fine particles.

• 한국가시화정보학회:학술대회논문집
• /
• 한국가시화정보학회 2002년도 추계학술대회 논문집
• /
• pp.7-10
• /
• 2002

A novel two-phase PIV algorithm using a single camera has been proposed, which introduces a method of image-separation into respective phase images, and is applied to freely rising single bubble. Gas bubble, tracer particle and background each have different gray intensity ranges on the same image frame when reflection and dispersion in the phase interface are intrinsically eliminated by optical filters and fluorescent material. Further, the signals of the two phases do not interfere with each other. Gas phase velocities are obtained from the separated bubble image by applying the two-frame PTV. On the other hand, liquid phase velocities are obtained from the tracer particle image by applying the cross-correlation algorithm. Moreover, in order to increase the SNR (signal-to-noise ratio) of the cross-correlation of tracer particle image, image enhancement is employed.

• 한국물환경학회지
• /
• 제27권6호
• /
• pp.877-884
• /
• 2011

In this paper, the removal characteristics of dissolved organic carbon (DOCs) by micro bubble ozonation process and $O_3/UV$ process were comparatively studied. In the point of DOC removing reaction coefficient, micro bubble ozonation system and $O_3/UV$ process had not significant difference, $0.0120sec^{-1}$ and $0.0141sec^{-1}$. Therefore micro bubble ozonation process is more suitable for tertiary treatment of sewage in the point of installation and maintenance cost-reducing. The optimum ozone injection rate was 2.0 g $O_3/g$ DOC and HRT was 3 min for the micro bubble ozonation process. The removal efficiency of DOC and SUVA in micro bubble ozonation system was 32.8% and 58.3% respective. Biological aerated filter (BAF) process was installed to remove soluble organic material increased by micro bubble ozonation system. And the effluent BOD of BAF was below 1.0 mg/L. In the view of cost-effectiveness, $O_3/BAF$ process was more profitable than $O_3/UV/BAF$ process for tertiary treatment of sewage. In order to nitrify ammonia in the BAF process completely, $NH_4{^+}-N$ concentration in the influent water of BAF should be designed considering low water temperature in the winter season.

• 한국컴퓨터정보학회논문지
• /
• 제22권12호
• /
• pp.117-123
• /
• 2017

The personalized search algorithm is a search system that analyzes the user's IP, cookies, log data, and search history to recommend the desired information. As a result, users are isolated in the information frame recommended by the algorithm. This is called 'Filter bubble' phenomenon. Most of the personalized data can be deleted or changed by the user, but data stored in the service provider's server is difficult to access. This study suggests a way to neutralize personalization by keeping on sending random query words. This is to confuse the data accumulated in the server while performing search activities with words that are not related to the user. We have analyzed the rank change of the URL while conducting the search activity with 500 random query words once using the personalized account as the experimental group. To prove the effect, we set up a new account and set it as a control. We then searched the same set of queries with these two accounts, stored the URL data, and scored the rank variation. The URLs ranked on the upper page are weighted more than the lower-ranked URLs. At the beginning of the experiment, the difference between the scores of the two accounts was insignificant. As experiments continue, the number of random query words accumulated in the server increases and results show meaningful difference.

• 한국도서관정보학회지
• /
• 제43권3호
• /
• pp.353-384
• /
• 2012

본 연구는 최근에 이슈가 되고 있는 필터버블 문제와 프라이버시 침해 문제가 이용자맞춤형서비스를 제공하는 도서관과 무관하지 않다는 인식에서 수행되었다. 본 연구에서는 최첨단기술을 활용하는 위치기반서비스, 상황인식서비스, 책추천서비스, RFID기반서비스, 클라우드서비스가 어떤 측면에서 개인정보침해 및 프라이버시 침해가능성이 있는지를 고찰하였다. 또한 특정 서비스 이용을 위해 개인정보를 제공한 이용자는 개인정보를 포기한 것으로 보아야 하는지, 국내 도서관에서 도서관 이용자의 프라이버시 문제가 논의된 적이 있는지, 필터버블 문제가 도서관 이용자에게 줄 수 있는 위험성과 해결책은 무엇인지에 대해서도 간단히 논의하였다. 본 연구는 도서관 프라이버시에 대한 초기단계의 연구로서 향후 국내 프라이버시 연구의 기초자료로 활용될 수 있기를 바란다.

• 한국주조공학회지
• /
• 제36권6호
• /
• pp.208-214
• /
• 2016

Casting defects, which are closely related to entrapped air bubbles and metallic oxides, occur very frequently in the casting process. Many researchers have shown that these defects can be reduced by adopting an appropriate gating system design. But, it is difficult for field engineers to identify a specific gating system that is more appropriate for their products. In this study, we tried to draw a comparison of gating system designs with and without ceramic foam filters. A ceramic foam filter was added to the horizontal runner just after the sprue to prevent air bubble generation and to reduce turbulence without change of the gating system design. To verify the effects of initial pouring velocity, the experiment was conducted with four different amounts of water volume in the reservoir. Results of the water modeling experiment applying the filter showed remarkably changed flow characteristics. Although the study confirmed that use of the filter may change the flow characteristics, it needs to be noted that only filter use alone cannot solve all the problems caused by a poorly designed gating system.

• 한국경제지리학회지
• /
• 제17권1호
• /
• pp.147-159
• /
• 2014

본 연구는 2003년 11월부터 2013년 8월까지의 전국, 수도권, 비수도권, 강남, 강북지역 아파트 매매가격의 합리적 버블을 전체기간과 글로벌금융위기 전 후로 기간을 나누어 상태공간모형과 칼만필터를 이용해 추정하였다. 전체기간 중에 강남은 합리적 버블이 25.4%로 가장 높고 강북 21.3%, 수도권 20.1%, 전국 18.9%, 비수도권 14.3%로 나타났다. 글로벌 금융위기 이전에는 강남이 26.7% 강북 19.3%로 강남이 강북보다 약 7.4% 정도 버블이 높게 형성되어 있다. 이에 반해 글로벌 금융위기 이후에는 강남 13.2%, 강북 10.7%로 버블이 많이 붕괴되었으나 오히려 비수도권 지역은 이전기간 4.2%에서 이후기간 19.0%로 약 15% 상승을 하였다. 이는 강남, 강북을 포함한 수도권은 매매가격이 하락하고 임대료는 상승을 하였고 비수도권 지역은 공공기관 이전 등 각종 개발호재로 인해 매매가격이 상승한 것이 주요원인으로 생각된다.

• 한국인터넷방송통신학회논문지
• /
• 제22권3호
• /
• pp.25-30
• /
• 2022

본 연구는 러시아-우크라이나 전쟁(2022)의 특징인 유튜브 등 SNS 추천알고리즘 필터버블 강화현상과 하이브리드 전쟁의 승패 요인에 관한 연구이다. 이 전쟁은 하이브리드전으로 규명되며, SNS 추천알고리즘 기반 뉴미디어의 활용은 정치적 레버리지를 넘어서 전쟁의 승부를 결정짓는 요소로 부상하고 있다. 이로 인해, 필터버블 현상이 시청자들에게 노출되는 정보의 제한을 가져온다는 확증편향의 사전적 의미를 넘어서고 있다. 우크라이나 젤렌스키 대통령이 키예프에서 항전을 독려한 유튜브 동영상의 경우 702만의 조회 수를 기록했지만, 푸틴의 연설은 80만에 그친 것은 추천알고리즘이 푸틴의 연설을 노출하지 않았다는 방증이다. 이러한 SNS 추천알고리즘의 노출 전쟁은 미국(유튜브, 트위터, 페이스북)과 중국(틱톡) 빅테크 기업의 알고리즘 전쟁으로 발전되는 경향을 보인다. 미국기업의 영향으로 우크라이나는 국제적인 지원을 받을 수 있게 되었고, 러시아는 중국기업의 영향으로 푸틴의 지지율이 80 프로가 넘는 상반된 결과가 도출되고 있다. 이러한 알고리즘 권력화는 '필터버블'에 의해 여론의 확증편향에 기반을 두고 있기에 이 왜곡 현상에 대한 새로운 가이드라인 설정을 이른 시일 안에 제시해야 한다는 정당성이 이번 러시아-우크라이나 전쟁을 통해서 주목받고 있다.

• 한국가시화정보학회지
• /
• 제2권1호
• /
• pp.39-45
• /
• 2004

A time-resolved two-phase PIV system using a single camera has been developed, which introduces a method of image separation into respective phase images, and is applied to freely rising single bubble. Gas bubble, tracer particle and background have different gray intensity ranges on the same image frame when reflection and dispersion in the phase interface are intrinsically eliminated by optical filters and fluorescent particles. Further, the signals of the two phases do not interfere with each other. Gas phase velocities are obtained from the separated bubble image by applying the two-frame PTV. On the other hand, liquid phase velocities are obtained from the tracer particle image by applying the cross-correlation algorithm. As a result, the bubble rises rectilinearly just after it is released from an injector and then has a zigzag motion in the far field. From the trajectory of the bubble, it is found that the period of the zigzag motion is closely related to the vortex shedding although the wavelength of it varies along its movement.