Hepatic Cellular Distribution of Silica Nanoparticles by Surface Energy Modification

Lee, A-Rang,Nam, Kibeom,Lee, Byeong Jun,Lee, Seoung-Woo,Baek, Su-Min,Bang, Jun-Sun,Choi, Seong-Kyoon,Park, Sang-Joon,Kim, Tae-Hwan,Jeong, Kyu-Shik,Lee, Dong Yun,Park, Jin-Kyu MDPI AG 2019 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.20 No.15

<P>The cellular distribution of silica nanoparticles (NPs) in the liver is not well understood. Targeting specific cells is one of the most important issues in NP-based drug delivery to improve delivery efficacy. In this context, the present study analyzed the relative cellular distribution pattern of silica NPs in the liver, and the effect of surface energy modification on NPs. Hydrophobic NP surface modification enhanced NP delivery to the liver and liver sinusoid fFendothelial cells (LSECs). Conversely, hydrophilic NP surface modification was commensurate with targeting hepatic stellate cells (HSCs) rather than other cell types. There was no notable difference in NP delivery to Kupffer cells or hepatocytes, regardless of hydrophilic or hydrophobic NP surface modification, suggesting that both the targeting of hepatocytes and evasion of phagocytosis by Kupffer cells are not associated with surface energy modification of silica NPs. This study provides useful information to target specific cell types using silica NPs, as well as to understand the relationship between NP surface energy and the NP distribution pattern in the liver, thereby helping to establish strategies for cell targeting using various NPs.</P>

Using Experts Among Users for Novel Movie Recommendations

Lee, Kibeom,Lee, Kyogu Korean Institute of Information Scientists and Eng 2013 Journal of Computing Science and Engineering Vol.7 No.1

The introduction of recommender systems to existing online services is now practically inevitable, with the increasing number of items and users on online services. Popular recommender systems have successfully implemented satisfactory systems, which are usually based on collaborative filtering. However, collaborative filtering-based recommenders suffer from well-known problems, such as popularity bias, and the cold-start problem. In this paper, we propose an innovative collaborative-filtering based recommender system, which uses the concepts of Experts and Novices to create fine-grained recommendations that focus on being novel, while being kept relevant. Experts and Novices are defined using pre-made clusters of similar items, and the distribution of users' ratings among these clusters. Thus, in order to generate recommendations, the experts are found dynamically depending on the seed items of the novice. The proposed recommender system was built using the MovieLens 1 M dataset, and evaluated with novelty metrics. Results show that the proposed system outperforms matrix factorization methods according to discovery-based novelty metrics, and can be a solution to popularity bias and the cold-start problem, while still retaining collaborative filtering.

Longitudinal and Lateral Integrated Safe Trajectory Planning of Autonomous Vehicle via Friction Limit

Kibeom. Lee,Dongsuk. Kum 제어로봇시스템학회 2020 제어로봇시스템학회 국제학술대회 논문집 Vol.2020 No.10

Due to the development of advanced driver assistance systems (ADAS) and autonomous vehicle (AV) technology, various path planning algorithms are being developed. However, most path planning algorithms operate in general and safety scenarios, and in emergency scenarios, the autonomous emergency brake (AEB) and autonomous emergency steering (AES) systems are operated limitedly. In an emergency situation in which the vehicle dynamic characteristics changed, planning a safe trajectory that can be safely tracking in necessary. In this study, a safe trajectory planning method in which the vehicle does not lose stability by using combined longitudinal and lateral acceleration vectors is proposed. The combined acceleration vector is limited by friction limit. The proposed trajectory planning algorithm is evaluated by simulation in a single obstacle scenario through comparison with existing AEB and AES algorithms. The simulation results show the proposed algorithm generates only safe trajectory that guarantee the vehicle stability, excluding dangerous trajectories when the AEB and AES algorithms operated.

Using Experts Among Users for Novel Movie Recommendations

Kibeom Lee,Kyogu Lee 한국정보과학회 2013 Journal of Computing Science and Engineering Vol.7 No.1

The introduction of recommender systems to existing online services is now practically inevitable, with the increasing number of items and users on online services. Popular recommender systems have successfully implemented satisfactory systems, which are usually based on collaborative filtering. However, collaborative filtering-based recommenders suffer from well-known problems, such as popularity bias, and the cold-start problem. In this paper, we propose an innovative collaborative-filtering based recommender system, which uses the concepts of Experts and Novices to create finegrained recommendations that focus on being novel, while being kept relevant. Experts and Novices are defined using pre-made clusters of similar items, and the distribution of users’ ratings among these clusters. Thus, in order to generate recommendations, the experts are found dynamically depending on the seed items of the novice. The proposed recommender system was built using the MovieLens 1 M dataset, and evaluated with novelty metrics. Results show that the proposed system outperforms matrix factorization methods according to discovery-based novelty metrics, and can be a solution to popularity bias and the cold-start problem, while still retaining collaborative filtering.

Using Dynamically Promoted Experts for Music Recommendation

Lee, Kibeom,Lee, Kyogu IEEE 2014 IEEE transactions on multimedia Vol.16 No.5

<P>Recommender systems have become an invaluable asset to online services with the ever-growing number of items and users. Most systems focused on recommendation accuracy, predicting likable items for each user. Such methods tend to generate popular and safe recommendations, but fail to introduce users to potentially risky, yet novel items that could help in increasing the variety of items consumed by the users. This is known as popularity bias, which is predominant in methods that adopt collaborative filtering. Recently, however, recommenders have started to improve their methods to generate lists that encompass diverse items that are both accurate and novel through specific novelty-driven algorithms or hybrid recommender systems. In this paper, we propose a recommender system that uses the concepts of Experts to find both novel and relevant recommendations. By analyzing the ratings of the users, the algorithm promotes special Experts from the user population to create novel recommendations for a target user. Thus, different users are promoted dynamically to Experts depending on who the recommendations are for. The system used data collected from Last.fm and was evaluated with several metrics. Results show that the proposed system outperforms matrix factorization methods in finding novel items and performs on par in finding simultaneously novel and relevant items. This system can also provide a means to popularity bias while preserving the advantages of collaborative filtering.</P>

Improving Diversity of Radio Playlists with the Aid of Recommender Systems

Kibeom Lee(이기범),Ziwon Hyung(형지원),Namjun Kang(강남준),Kyogu Lee(이교구) 한국방송학회 2014 한국방송학회 학술대회 논문집 Vol.2014 No.4

국제기구의 의사결정과 관련하여 `Global Administrative Law`(GAL) 개념 도입의 필요성 주장과 이에 대한 국제법적 반론

이기범(LEE Kibeom) 대한국제법학회 2015 國際法學會論叢 Vol.60 No.1

`Global Administrative Law`(이하 “GAL”)라 불리는 새로운 법체계에 대한 논의가 이어지고 있다. GAL 개념 정립을 주장하는 사람들은 개인 또는 회사에게 영향을 미치는 국제기구의 의사결정은 법체계에 의해 규율되어야 하는데 이 법체계로 GAL 개념 도입을 주장하고 있다. 더구나 국제기구 또는 외교회의를 통한 국제입법 시 개인 또는 NGO도 그 입법에 참여할 수 있는 권리가 GAL을 통해 보장되어야 함을 언급하고 있다. 이러한 주장은 전통적인 국제법의 연원인 조약 또는 국제관습법이 아닌 국제기구의 의사결정이 실제적으로 발휘하고 있는 영향력을 강조하고, 국제입법의 주체를 개인 또는 NGO로 확장한다는 차원에서 전통적인 국제법 개념에 대한 하나의 도전이 되고 있다. 특히 GAL 개념의 지지자들은 GAL의 연원으로 국내법 또한 인정하여 국내 행정법의 기본원칙들이 국제기구의 의사결정을 규율해야 한다는 주장을 하고 있다. 즉, 이들은 현재 국제기구의 의사결정이 그 의사결정의 영향을 받을 수 있는 개인 또는 회사의 참여 없이 비민주적으로 이루어지고 있으며, 그 의사결정으로 인하여 개인 또는 회사의 이익이 보장받을 수 없는 위험이 존재하고 있다고 보고 있다. 비록 GAL 개념을 지지하는 사람들의 독특한 시각이 존중될 가치가 있다 하더라도 이들이 GAL이라는 법체계의 탄생을 논증하는데 있어 국제기구의 의사결정 그리고 국제입법의 과정과 관련하여 기존 국제법의 이론을 정확히 이해하지 못하고 있는 것에 대해서는 아쉬움을 금할 수 없다. 또한 이들은 GAL이라는 제3의 법체계의 정립과 관련하여 그 법체계의 주체, 연원, 적용 영역 또는 대상 등을 정확히 정의하지 못하고 있다. GAL 개념을 제시하는 것은 국제적인 차원에서 개인 또는 NGO의 영향력을 법적으로 확대하기 위한 시도에 불과하다. 하지만 국제기구의 의사결정 절차를 규율하는 가장 좋은 방법은 관련 국제기구의 설립조약을 개정하거나 실제로 의사결정을 하는 국제기구의 관련 기관이 자신의 의사결정 과정을 규율하는 확립된 지침 또는 관행을 수립하는 것이다. 그리고 개인 또는 NGO의 의사는 현재의 국제입법 과정에서는 국가에 의해 대표되어 나타날 수밖에 없다. 물론 국내 시민사회의 영향력이 관련 국가들의 외교관들이 교섭을 시작하는데 있어 영향을 끼칠 수 있는 것은 분명하지만 이러한 영향력 행사를 법적으로 보장하는 것은 국제입법 과정을 복잡하게 할 뿐이다. 따라서 현재의 국제법체계에 GAL 개념을 도입할 필요성을 찾기는 어렵다고 할 수 있을 것이다. It is debatable whether a new legal system called `Global Administrative Law`(hereafter referred to as “GAL”) exists. Some argue that the decision-making of international organization, which has an impact on individuals or companies, should be regulated by a legal system, and therefore insist upon the need of GAL Moreover, they think that individuals or NGOs should have a right (conferred to y the concept of GAL) to participation in international law-making through international organizations or diplomatic conferences. This contention is a challenge to the present concepts of international law because it means that the decision-making of international organizations would exert more influence than the main sources of international law (treaties and customary international law), and that individuals (or NGOs) would be regarded as the subjects of international law, especially in international law-making. Advocates for the concept of GAL contend that domestic law can be the sources of GAL, and that some principles of domestic administrative law should govern the decision-making of international organizations. The reason for the contention are that the decision-making process of international organizations might be undemocratic without any participations of individuals or companies, and that the interests of individuals or companies would then be put at risk. Although their support for the concept of GAL should be respected, it is regrettable that they do not precisely understand the theories of international law regarding the decision-making of international organizations and international law-making. In addition, they fail to define the subjects and sources of GAL or the areas that can be regulated by the GAL system. The hidden intent for introducing the system of GAL is that individuals or NGOs want to extend their influence on the decision-making process of international organizations. However, the best way to govern the decision-making of an international organization is to amend the constituent documents of the international organization or to establish guidelines or practices by a decision-making organ within the international organization. In addition, the intent of individuals or NGO should be represented by the will of a State. Although civil society has considerable influence on the diplomatic negotiations, an NGO`s legal right to participation in the negotiations would make international law-making exceedingly complicated. It is, therefore, unnecessary for contemporary international law to accept the establishment of the GAL system.

입구형상 변화에 따른 평면제트의 혼합에 대한 수치해석

이기범(Kibeom Lee),박태선(Tae Seon Park) 한국추진공학회 2022 한국추진공학회 학술대회논문집 Vol.2022 No.11

해양경계획정에 적용할 수 있는 ‘3단계 방법론’에 대한 비판적 소고

이기범(Lee Kibeom) 대한국제법학회 2020 國際法學會論叢 Vol.65 No.2

2009년 ICJ의 Black Sea (Romania v. Ukraine) 사건이 소위 ‘3단계 방법론’을 확립한 이후 3단계 방법론은 해양경계획정을 수행하는 국제재판소의 표준적 방법론으로 자리를 잡았다. 배타적 경제수역 또는 대륙붕의 경계획정을 규율하는 법적 구속력 있는 규칙은 유엔해양법협약 제74조 제1항 또는 제83조 제1항에 규정되어 있는 것처럼 그리고 국제관습법상으로도 ‘형평한 해결의 도달’이다. 이와 같이 모호한 법 규칙을 적용하기 위해 국제재판소가 확립한 3단계 방법론은 객관성 또는 예측가능성을 담보한다는 차원에서 찬사를 받고 있다. 그럼에도 3단계 방법론은 내재적으로 한계를 지니고 있다. 제1단계에서는 잠정적인 등거리선을 설정할 때 필요한 기점들이 주관적으로 선택될 수 있다는 것이 가장 큰 문제이다. 이는 등거리 방법 자체가 객관적이라 해도 등거리 방법의 ‘적용’은 주관적일 수 있다는 것을 의미한다. 관련 사정들이 제2단계에서만 그 역할을 수행할 수 있는 것처럼 보이는 것도 문제라 지적할 수 있다. 하지만 제1단계에서 관련 사정들의 존재 때문에 잠정적인 등거리선이 아닌 잠정적인 이등분선이 설정될 수도 있는 것처럼 관련 사정들이 반드시 제2단계에서만 고려되지는 않는다. 그리고 ‘불균형성 점검’, 즉 제3단계는 그 존재 의의부터 의심받고 있다. 오늘 현재까지 그 어떤 국제재판소 판례도 제3단계에서 제1단계와 제2단계를 통해 그려진 경계선을 이동시킨 적이 없기 때문이다. 이와 같은 내재적 한계를 고려했을 때 3단계 방법론은 ‘방법론’으로서의 의의만 가질뿐 3단계 방법론이 그 이상의 함의를 포함하고 있다고 보기 어렵다. 즉, 3단계 방법론이 적용되어 투명성과 해양경계획정 과정의 예측가능성이 확보되거나 제고된다 하여 해양경계획정의 궁극적 목표인 형평한 해결의 도달이 자동적으로 이루어지는 것은 아니다. 만약 3단계 방법론이 아닌 다른 방법론을 원용하여 해양경계획정의 목표인 형평한 해결의 도달이 이루어질 수 있다면 이는 3단계 방법론을 맹목적으로 고수할 필요가 없다는 것을 의미한다. 결국 여전히 해양경계획정을 지배하는 개념은 각 해양경계획정 사건마다 제각각인 ‘관련 사정들’이다. 따라서 3단계 방법론이라는 단계적 방법론의 고수가 형평한 해결의 도달을 어렵게 한다면 해당 해양경계획정 사건만의 관련 사정들을 고려하여 적절한 다른 방법론을 원용하는 것이 국제재판소가 취할 수 있는 가장 바람직한 태도가 될 것이다. Since the 2009 Black Sea (Romania v. Ukraine) case of the International Court of Justice (ICJ), the so-called ‘three-stage methodology’ has been employed as the ‘standard’ methodology by international courts and tribunals dealing with maritime boundary delimitation. The binding rule governing the delimitation of the exclusive economic zone or the continental shelf is the ‘achievement of an equitable solution’, as stipulated in Article 74(1) or 83(1) of the United Nations Convention on the Law of the Sea (UNCLOS) and recognized as part of customary international law by the ICJ. The three-stage methodology has been established to apply this open-textured rule in a given delimitation case, and the methodology is often complimented because it seems to assure not only objectivity but also predictability in applying the rule. Nevertheless, the three-stage methodology has its limitations. Firstly, it is, at the first stage, possible to subjectively select base points necessary to construct a provisional equidistance line. This means that the ‘application’ of the equidistance method would be subjective although the method in itself is objective. Secondly, within the framework of the three-stage methodology, relevant circumstances seem to take up their position only at the second stage. However, because of the existence of relevant circumstances, a provisional bisector line could be drawn at the ‘first’ stage, instead of a provisional equidistance line. Thirdly, it is questionable whether or not the third stage conducting the disproportionality test is a necessary step in maritime boundary delimitation. The reason for this is that any delimitation lines constructed through the first and second stages have not been adjusted at the third stage since the Black Sea (Romania v. Ukraine) case. Taking into account the limitations of the three-stage methodology described above, the methodology has to be regarded as a ‘just’ methodology. Moreover, transparency and the predictability of the delimitation process as a whole enhanced through the three-stage methodology do not automatically lead to the achievement of an equitable solution. If another methodology produces an equitable solution in a specific delimitation case, it could be employed, instead of the three-stage methodology. In fact, the concept of ‘relevant circumstances’ predominates the process of delimiting maritime boundaries for the achievement of an equitable solution. It is, therefore, desirable for international courts and tribunals to adopt an appropriate methodology taking into consideration relevant circumstances in a given delimitation case, without the need to only adhere to the employment of the three-stage methodology.

자율주행 차량의 실시간 측위와 경로 계획 특성을 고려한 경로 추종 제어

이기범(Kibeom Lee),전승민(Seungmin Jeon),금동석(Dongsuk Kum) 한국자동차공학회 2019 한국자동차공학회 Workshop Vol.2019 No.5