Cheol-woo Lee
Yonsei University · Environmental Science
About the Lab
Professor Cheol-woo Lee's research lab specializes in image processing, computer vision, and computational modeling with a focus on advanced contrast enhancement techniques and graph-based algorithms for image analysis. The lab develops innovative methods rooted in statistical modeling and optimization, such as layered difference representation in 2D histograms and multi-agent random walker systems for image segmentation and cosegmentation. Additionally, the lab explores sociopolitical dimensions of citizenship and national identity, particularly in the context of transnational migration and the redefinition of belonging in the era of global mobility.
Research Overview
Research Output Trend
Figures are computed from collected data and may differ slightly.
Selected Papers
15A novel contrast enhancement algorithm based on the layered difference representation of 2D histograms is proposed in this paper. We attempt to enhance image contrast by amplifying the gray-level differences between adjacent pixels. To this end, we obtain the 2D histogram h(k, k + l ) from an input image, which counts the pairs of adjacent pixels with gray-levels k and k + l , and represent the gray-level differences in a tree-like layered structure. Then, we formulate a constrained optimization
A novel contrast enhancement algorithm based on the layered difference representation is proposed in this work. We first represent gray-level differences at multiple layers in a tree-like structure. Then, based on the observation that gray-level differences, occurring more frequently in the input image, should be more emphasized in the output image, we solve a constrained optimization problem to derive the transformation function at each layer. Finally, we aggregate the transformation functions
A graph-based system to simulate the movements and interactions of multiple random walkers (MRW) is proposed in this work. In the MRW system, multiple agents traverse a single graph simultaneously. To achieve desired interactions among those agents, a restart rule can be designed, which determines the restart distribution of each agent according to the probability distributions of all agents. In particular, we develop the repulsive rule for data clustering. We illustrate that the MRW clustering
This study brings to light the problem of identifying, and of determining the status of, ethnic Korean migrants who assert membership in the Korean national community. The influx of members of the ethnic diaspora in China and the former Soviet Union has posed challenges to South Korea's legal definition of national membership and its practice of keeping the boundaries of nationhood. In response to the challenges, South Korea has calibrated its administration for admitting those coethnics and dev
Abstract The phrase “decoupling of nation and state” has increasing currency in discussions of the transformation of citizenship and the state-people connection in this age of global migration. This study questions the soundness of characterising the current transformation in those terms. Asserting that the nexus between state and nation is being renegotiated and readjusted rather than disconnected or attenuated, the study highlights the multifaceted and multi-dimensional character of the state-
이 글은 시민권이 국민국가의 제도적 틀에서 벗어나 지구적 차원에서 재정립되고 있다는 소위 탈국가적 시민권 개념을 비판적으로 분석함으로써 시민권의 현 상태를 진단한다. 소이살과 제이콥슨의 제도주의적 탈국가론의 주장과 가정에서 쟁점을 추출하고, 그에 대한 여러 학자의 견해와 논점에 적합한 사실을 재조명함으로써 시민권 제도가 경험하는 변화를 바라보고 설명하는 인식의 틀을 개발하고자 하다. 이 글에서는 보편적 인간지위에 기초한 국제인권법이 얼마나 국가주권을 상위에서 제약하는가, 국가에의 소속이 더 이상 권리 배분의 주된 기준이 되지 않는가, 소속의 다중성(복수의 국적)과 다층성(여러 층위의 공동체에 소속)이 얼마나 국가와 개인의 전통적 관계를 동요시키는가, 글로벌 시민사회의 차원에서 맺어지는 관계에서 시민권의 새로운 지평을 발견할 수 있는가의 문제를 검토한다. 그러한 논의를 통해 탈국가적 시민권 개념이 부적합하다는 점을 지적하고, 국민국가적 시민권 개념 자체가 가지는 내재적 모순이 이주의
이중국적이 국민국가의 구성원리에 어긋나는 현상이라는 믿음은 이중국적을 도덕적, 정치적으로 적대시하는 사회 여론은 물론 비판적 시민권 연구자들 사이에도 공유되어 있다. 국민국가의 틀로부터 해방된 탈국가적 시민권을 전망하는 학자들은 이중국적을 용인하는 법정책의 확산과 이중국적의 빈발을 시민권의 탈국가화를 보여주는 징후로 간주하기도 한다. 이 글에서는 그와 같은 관점을 반박한다. 이중국적이 복수의 국적국의 주권을 공히 약화시키지 않으며 국가의 경계를 유린하는 초국가적 이주자의 삶이 이중국적과 필연적으로 연결되어 있지 않다는 선행 연구자의 반론을 계승하면서, 이중국적이 국민국가가 인적인 외연을 넓히는 주권의 탈영토화 및 위로부터의 초국가성, 그리고 영토에 대한 지배를 확고히 하려는 주권의 재영토화의 전략 수단으로 사용되고 있음을 여러 논의와 사례를 원용하여 보여준다. 이 글은 이중국적이 국민국가의 논리에 반하는 것이 아니라 그것에 터잡고 있음을 강조한다. 결론하여, 이중국적은 인적 집단인
A novel power-constrained contrast enhancement algorithm for organic light-emitting diode (OLED) displays is proposed in this work. We first develop the log-modified histogram equalization (LMHE) scheme, which reduces overstretching artifacts of the conventional histogram equalization technique. Then, we model the power consumption in OLED displays, and incorporate it into LMHE to achieve the optimal tradeoff between contrast enhancement and power saving. Simulation results demonstrate that the
Gene expression levels of choriogenin, vitellogenin, and estrogen receptor were determined using a reverse transcription-polymerase chain reaction (RT-PCR) technique after exposure to estrogenic chemicals to compare the sensitivities of the biomarkers of endocrine disruption in medaka, Oryzias latipes. Mature male medaka were treated with a single dose of 100 μ/l of 17α-ethinylestradiol, nonylphenol, and bisphenol A for 6 days, then RNA was extracted from the livers of treated fish for RT-PCR. P
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