임플란트 즉시 식립에 의한 연속된 상악 전치부의 심미적 수복 증례

이예찬,심준성,이재훈,이근우,Lee, Ye Chan,Shim, Jun Sung,Lee, Jae Hoon,Lee, Keun Woo 대한치과보철학회 2017 대한치과보철학회지 Vol.55 No.4

상악 전치부를 발치 해야 하는 경우, 즉시 식립을 통한 임플란트 고정성 보철물의 수복을 고려할 수 있다. 이 경우, 수술 횟수 및 치료기간의 감소, 흡수가 일어나지 않은 잔존 골상에 식립이 가능하다는 장점이 있으나, 연속된 상악 전치부인 경우 임플란트와 임플란트간 거리에 대한 고려 및 예지성 있는 치료를 위한 정확한 진단 및 치료계획의 수립이 추가적으로 고려되어야 한다. 본 증례에서는 63세 남환의 잔존치근을 발거 후 연장된 상악 전치부에 골이식을 동반한 2개의 임플란트 즉시 식립 및 임시 보철물을 장착 후, 임플란트 고정성 보철물로 수복하여 심미적, 기능적으로 만족할만한 임상 결과를 보였기에 이를 보고하는 바이다. In the case of an extraction in the maxillary anterior region, immediate placement of implant-supported fixed prosthesis can be considered as a treatment option. Fewer surgical operations, reduced treatment time, and optimal availability of existing bone are obvious advantages of the method; however, when applied in the continuous maxillary anterior region, inter-implant distance must be carefully considered, as well as accurate diagnosis and treatment planning for predictable outcome. In this case report, immediate placement of two implants in the continuous maxillary anterior along with bone graft following the extraction of root rests, and the restoration of provisional and implant-supported fixed prosthesis on a 63-year-old patient had resulted in both esthetically and functionally satisfactory clinical outcomes.

배달로봇의 갓길주행을 위한 자율 주행 알고리즘 분석

이예찬(Ye-Chan Lee),김태훈(Tae-Hoon Kim),나지영(Ji-Young Na),윤지원(Ji-Won Yoon),이세훈(Se-hun Lee),이한용(Han-yong Lee) 한국정보기술학회 2023 Proceedings of KIIT Conference Vol.2023 No.6

강섬유를 혼입한 시멘트 복합체의 전기적 특성

이예찬(Lee, Yae Chan),김규용(Kim, Gyu Yong),남정수(Nam, Jeong Soo),손민재(Son, Min Jae),편수정(Pyeon, Su Jeong),서동균(Suh, Dong Kyun) 한국콘크리트학회 2021 한국콘크리트학회 학술대회 논문집 Vol.33 No.2

본 연구는 강섬유를 시멘트 복합체에 혼입하여 전도성 네트워크를 형성하고자 하였으며, 이를 기반으로 강섬유 보강 시멘트 복합체의 섬유의 길이, 혼입률 및 재령에 따른 나이퀴스트 선도 거동 및 전기전도도를 비교·분석하는데 목적을 둔다. The purpose of this study is to compare and analyze the nyquist plot behavior and electrical conductivity according to the length, volume fraction of fiber and curing days of the steel fiber-reinforced cementitious composites.

자기공명영상장치 촬영 시 다양한 재활 동작이 가능한 유연 손 보조 장갑

이예찬(Yechan Lee),조성현(Seong Hyeon Jo),김유성(Yusung Kim),박형순(Hyung-Soon Park) 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.11

The relationship between movement and brain activation is widely studied using functional magnetic resonance imaging (fMRI). Magnetic resonance (MR) compatible equipment are required to help patients hand movement inside the fMRI machine to examine the relationship between hand movement and brain activation in patients with neurological disorders accompanying hand impairment. A number of MR compatible devices have been developed, but none has been developed to help with various hand postures. This paper suggested a soft robotic glove that is compatible with MR and allows for several hand postures. The MR imaging of MRI phantom was used to verify the gloves MR compatibility. The reported images did not show any significant degradation or SNR difference whether glove is activated or not. It was anticipated that the suggested MR compatible soft robotic glove could be used to examine the connection between various hand postures and brain activation in people with neurological disorders.

자기공명영상장치 촬영 시 다양한 재활 동작이 가능한 유연 손 보조 장갑

이예찬(Yechan Lee),조성현(Seong Hyeon Jo),김유성(Yusung Kim),박형순(Hyung-Soon Park) 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.11

The relationship between movement and brain activation is widely studied using functional magnetic resonance imaging (fMRI). Magnetic resonance (MR) compatible equipment are required to help patients hand movement inside the fMRI machine to examine the relationship between hand movement and brain activation in patients with neurological disorders accompanying hand impairment. A number of MR compatible devices have been developed, but none has been developed to help with various hand postures. This paper suggested a soft robotic glove that is compatible with MR and allows for several hand postures. The MR imaging of MRI phantom was used to verify the gloves MR compatibility. The reported images did not show any significant degradation or SNR difference whether glove is activated or not. It was anticipated that the suggested MR compatible soft robotic glove could be used to examine the connection between various hand postures and brain activation in people with neurological disorders.

낙동강하류 생태공원의 조류 현황

이예찬(Yechan Lee),여운상(Unsang Yeo),오동하(Dongha Oh),성기준(Kijune Sung) 한국생태공학회 2021 한국생태공학회지 Vol.8 No.1

The estuary of the Nakdong River is the largest habitat for migratory birds in Korea, and it is an area with high conservation value due to its wide tidal flats and wetlands with high biodiversity and abundant fishery resources. However, many changes are taking place, such as the destruction of migratory bird habitats due to urban expansion and development. In this study, the role and impact of ecological parks are analyzed by analyzing the current status of birds in the Nakdong Estuary Ecological Park, and furthermore, it is intended to be used as data for ecological management. Migratory birds visiting the estuary of the Nakdong River use the ecological park, but the birds found in the ecological park had a high proportion of resident birds. Also, the species richness index and biodiversity index (species diversity) were lower in the ecological park compared to the Nakdong River estuary.

온라인 소비자 후기 명예훼손 판결에서 나타난 표현의 자유와 한계

이예찬(Ye Chan Lee),이재진(Jae Jin Lee) 한국언론학회 2021 한국언론학보 Vol.65 No.5

In 2012, the court judgment in the Postpartum Care Center case, in which the court decided in favor of freedom of expression, provided a reasonable test on defamation by online consumer reviews. As such, this study analyzed 63 court cases that were announced after the aforementioned judgment to examine the status of the lawsuits, the trend of the citation of the Postpartum Care Center case ruling, and the court’s position on the “purpose of slander,” which is an essential element of defamation under the Information and Communication Network Act. The findings indicate that the appeal rate of the criminal judgments involving defamation by consumer reviews was 47.4% (61.1% for the first-instance judgments and 23.8% for the second-instance judgments). About 60% cases were confirmed at an appellate level or higher. The rate of acquittal was 45.9%, and the acquittal rate reached 65.4% for defamation cases based on facts, whereas all cases of defamation cases with false facts were convicted. And that of judgments maintained by appellant courts was 90.5%. Interestingly, the courts imposed fines on convicts in all cases where the defendants were convicted only of defamation, and the average amount of the fines stood at 1.08 million KRW. Among the cases, those citing the Postpartum Care Center case was 41.7%, and the citation rate in defamation cases with false facts was 53.8%, which is 43.8%p higher than that of cases with false facts. The acquittal rate when citing the Postpartum Care Center was 86.7%, which is 67.7%p higher than the judgments that did not. The fact that the acquittal rate reached 45.9% raises serious concerns about abuse of the right to prosecute in consumer defamation cases. However, the courts showed that they are trying to protect consumers rights and freedom of expression through a process of appropriately comparing and balancing the degree of defamation of the victim and the benefits of the free exchange of information and opinions of Internet users. In other words, if it was judged that the consumer reviews were posted for the purpose of public interest as truthful facts, the accused was acquitted by denying the purpose of slander. But when consumer reviews are posted indiscriminately in spaces that can be accessed by anyone: The victim can be identified from the content; the review contains personal attacks on the victim; the mode of expression is excessive in terms of several aspects, such as the number of posts; and the main purpose is to pursue the defendant’s personal agenda rather than providing information to other consumers, the courts recognized the purpose of slander. In other words, although the defendant wrote a review based on objective facts, if it was deemed to serve the purpose of slandering the victim considering the scope of distribution, the mode of expression, the mental distress that the victim may have suffered, and the posting process, the court found the defendant guilty.

섬유 종류에 따른 섬유 보강 시멘트 복합체의 전기적 특성에 대한 실험적 연구

이예찬 ( Lee Yae-chan ),김규용 ( Kim Gyu-yong ),한승현 ( Han Seung-hyeon ),최윤성 ( Choi Youn-sung ),김문규 ( Kim Moon-kyu ),남정수 ( Nam Jeong-soo ) 한국건축시공학회 2023 한국건축시공학회 학술발표대회 논문집 Vol.23 No.1

The purpose of this study is to compare and analyze the effect of type and volume fraction of fiber on the electrical conductivity and shielding effectiveness of cementitious composites. The large specific surface area of amorphous metallic fiber, as well as the high number of fibers per unit weight, provided an advantage in the formation of conductive path. As the result, the electrical conductivity of amorphous metallic fiber was evaluated to be higher, and the shielding effectiveness was also higher. However, the shielding effectiveness according to electrical conductivity was confirmed to have a threshold point, and further research is needed to improve it.

머신 러닝 기반 증류탑 온도 예측 모델의 성능 개선을 위한 저주파 통과 필터 적용

이예찬(Y. Lee),최영렬(Y. Choi),조형태(H. Cho),김정환(J. Kim) 한국생산제조학회 2020 한국생산제조시스템학회 학술발표대회 논문집 Vol.2020 No.7

머신 러닝과 데이터 전처리를 활용한 증류탑 온도 예측

이예찬 ( Yechan Lee ),최영렬 ( Yeongryeol Choi ),조형태 ( Hyungtae Cho ),김정환 ( Junghwan Kim ) 한국화학공학회 2021 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.59 No.2

화학 공정의 주요 설비 중 하나인 증류탑은 물질들의 끓는점 차이를 이용하여 혼합물에서 원하는 생산물을 분리하는 설비이며 증류 공정은 많은 에너지가 소비되기 때문에 최적화 및 운전 예측이 필요하다. 본 연구의 대상 공정은 공급처에 따라 원료의 조성이 일정하지 않아 정상 상태로 운전이 어려워 효율적인 운전이 어렵다. 이를 해결하기 위해 데이터 기반 예측 모델을 이용하여 운전 조건을 예측 할 수 있다. 하지만 미가공 공정 데이터에는 이상치 및 노이즈가 포함되어 있어 예측 성능을 향상시키기 위해 데이터 전처리가 필요하다. 본 연구에서는 인공 신경망 모델인 Long shortterm memory (LSTM)과 Random forest (RF)를 사용하여 모델을 최적화한 후, 데이터 전처리 방법으로 Low-pass filter와 One-class support vector machine을 사용하여 데이터 전처리 방법 및 범위에 따른 예측 성능을 비교하였다. 각 모델의 예측 성능과 데이터 전처리의 영향은 R²과 RMSE를 사용하여 비교하였다. 본 연구의 결과, 전처리를 통해 LSTM의 경우 R2은 0.791에서 0.977으로 RMSE는 0.132에서 0.029로 각각 23.5%, 78.0% 향상되었고, RF의 경우 R²은 0.767에서 0.938으로 RMSE는 0.140에서 0.050으로 각각 22.3%, 64.3% 향상되었다. A distillation column, which is a main facility of the chemical process, separates the desired product from a mixture by using the difference of boiling points. The distillation process requires the optimization and the prediction of operation because it consumes much energy. The target process of this study is difficult to operate efficiently because the composition of feed flow is not steady according to the supplier. To deal with this problem, we could develop a data-driven model to predict operating conditions. However, data preprocessing is essential to improve the predictive performance of the model because the raw data contains outlier and noise. In this study, after optimizing the predictive model based long-short term memory (LSTM) and Random forest (RF), we used a low-pass filter and one-class support vector machine for data preprocessing and compared predictive performance according to the method and range of the preprocessing. The performance of the predictive model and the effect of the preprocessing is compared by using R² and RMSE. In the case of LSTM, R² increased from 0.791 to 0.977 by 23.5%, and RMSE decreased from 0.132 to 0.029 by 78.0%. In the case of RF, R² increased from 0.767 to 0.938 by 22.3%, and RMSE decreased from 0.140 to 0.050 by 64.3%.