수동 광 네트워크 시스템에서의 다중접속제어 프로토콜에 관한 연구

최세라,장종욱,김진일 동의대학교 산업기술개발연구소 2000 産業技術硏究誌 Vol.14 No.-

FSAN(Full Service Access Network) Gx has discussed the cost-effective way to deploy the ATM-PON(Passive Optical Network) system that is suitable for providing broadband services. A common broadband PON applicable to many operators is increasing the world-wide market for the product. The MAC (Medium Access Control) protocol controls ONUs' (Optical Network Unit) access to the shared capacity on the PON, this protocol is very important if TDMA (Time Division Multiple Access) multiplexing is used to the upstream. In fact, there is a relatively large number of MAC proposals mentioning IEEE802.14. as a performance of protocol, for instance its channel throughput, packet delay, qualification of channel and complexity of MAC protocol. Therefore, this paper includes the contents which have analysis and performance of MAC protocol proposed in ATM PON environment with channel throughput and message delay. From the results, the compatible protocol is analyzed by the access method.

중학교 영어학습자의 듣기능력 신장 방안 연구 : 받아쓰기 훈련을 중심으로

한종임,최세라 이화여자대학교 교과교육연구소 1998 교과교육학연구 Vol.2 No.1

본 연구의 목적은 우리 나라 중학생들의 영어 듣기 능력을 향상시킬 수 있는 교수·학습 방법의 일환으로 듣기 지도를 위한 받아쓰기 활용 방안을 모색하는 데 있다. 받아쓰기가 영어 듣기 능력 신장에 미치는 학습 효과를 실증적으로 검증한 결과, 첫째, 받아쓰기 연습은 듣기 능력을 향상시킬 수 있으며, 둘째, 듣기 능력이 떨어지는 하위집단 학습자에게는 부분 받아쓰기가 더 효과적이고 듣기 능력이 비교적 좋은 상위집단 학습자들에게는 문장 전체의 이해를 요구하는 전체 받아쓰기가 더 효과적이라는 것이 입증되었다. 이리한 연구 결과가 영어교육 현장에 주는 시사점은 다음과 같다. 첫째, 영어교사들은 받아쓰기를 주로 평가로만 활용해 오던 종래의 방식에서 탈피하여 영어학습 초기 단계부터 듣기능력을 향상시킬 수 있는 방법으로 활용할 수 있으며, 둘째, 듣기와 연계된 받아쓰기의 효과를 극대화하기 위해서는 영어 학습초기 단계에서는 부분 받아쓰기의 비율을 전체 받아쓰기보다 더 많게 하고, 학생들의 듣기능력이 높아짐에 따라 점차 전체 받아쓰기에 역점을 두는 것이 바람직할 것으로 사료된다. The goal of Korean English education lies in the development of Korean EFL learners' communicative competence. Listening has been regarded as the most important and essential component in developing communicative competence since listening comprehension was proved to be an active skill. However, most English teachers do not know how to teach listening effectively in their class and students say that listening is the most difficult part among the four language skills. Therefore, research on improving listening ability is most needed in order to develop Korean EFL learners'communicative competence. The purpose of this study is to investigate the effect of dictation on the development of Korean middle school students' listening comprehension. The subjects of this study were first-year middle school sdents and they were divided into two groups: two experimental groups and a control group. The experimental groups were further divided into two groups: a spot dictation group and a full dictation group. The two experimental groups were given a dictation task in the consolidation stage of every En81ish class, while the control group was given the traditional consolidation stage without any dictation task. The main results of the study are as follows. First, the experimental groups showed significant improvement in listening comprehension, but the control group did not. Second, there was no significant difference between the spot dictation group and the full dictation group with respect to the improvement of listening comprehension. This indicates that the type of dictation is not a significant factor in improving listening skill. Third, the full dictation was proved to more effective to the high listening proficiency level learners, whereas the spot dictation was more effecsve to the low listening proficiency level learners. These results suggest that dictation can be used as one of the effective methods for improving Korean EFL learners' listening comprehension ability and the types of dictation should be determined according to learners' listening proficiency levels: the spot dictation is recomuended for the low level learners and the full dictation is recommended for the high level learners.

Effects of Medicinal herb Extracts and their Components on Steatogenic Hepatotoxicity in Sk-hep1 Cells

Choi, You-Jin,Yoon, Yu-Jin,Choi, Ho-Sung,Park, So-Ra,Oh, Se-Hee,Jeong, Se-Mi,Suh, Hyo-Ryung,Lee, Byung-Hoon Korean Society of ToxicologyKorea Environmental Mu 2011 Toxicological Research Vol.27 No.4

Herbal medicines are widely used in many countries for the treatment of many diseases. Although the use of herb extracts as alternative medicine is growing, their toxicological properties have not been thoroughly investigated. In this study, we have investigated the effects of water and ethanol extracts of 18 herbs on the hepatic lipid metabolism and steatogenic hepatotoxicity. Ethanol extracts of Cirsium japonicum, Carthamus tinctorius, Rehmanniae glutinosa (preparata), Polygala tenuifolia, Foeniculum vulgare, Polygonum multiflorum, and Acorus gramineus and water extracts of Polygonum multiflorum and Rehmanniae glutinosa induced lipid accumulation in Sk-hep1 human hepatoma cells as determined by Nile red staining. These extracts increased the luciferase activity of sterol regulatory element (SRE) and decreased that of peroxisome proliferator response element (PPRE), indicating the possibilities of enhanced fatty acid synthesis and decreased fatty acid oxidation. To identify the components responsible for the fat accumulation, we tested 50 chemicals isolated from the nine herbs. Apigenin, luteolin, pectolinarin and lupeol from Cirsium japonicum, 8-methoxypsoralen and umbelliferone from Foeniculum vulgare and pomonic acid and jiocerebroside from Rehmanniae glutinosa significantly increased the accumulation of lipid droplets. These results suggest that ethanol extracts of Cirsium japonicum, Carthamus tinctorius, Rehmanniae glutinosa (preparata), Polygala tenuifolia, Foeniculum vulgare, Polygonum multiflorum, and Acorus gramineus and water extracts of Polygonum multiflorum and Rehmanniae glutinosa can cause fatty liver disease by decreasing ${\beta}$-oxidation of fatty acid and increasing lipogenesis.

REBT와 ACT의 상담이론 비교

최세라(Se-ra Choi) 한국REBT인지행동치료학회 2024 한국REBT인지행동치료 Vol.4 No.1

본 연구는 인지정서행동치료(Rational Emotive Behavior Therapy: REBT)와 수용전념치료(Acceptance & Commitment : ACT)의 통합적 고찰을 통하여 인간의 부적응 행동 원인과 그 해결방안에 대한 이론적 근거를 제시하는데 목적이 있다. 이를 위해 문헌 연구를 실시하여 두 상담이론의 정의, 인간관, 주요개념, 상담과정, 기법 등을 비교· 분석하여 인간 부적응의 원인과 대처방안의 이론적 토대를 마련하였다. 연구결과, REBT와 ACT는 언어와 인지구조의 결합이 부적응 정서와 행동을 유발한다는 공통적 견해를 가지고 있음을 발견할 수 있었다. 왜곡된 인지로 형성된 부적응적 정서와 행동의 해결방안으로 REBT는 인지의 재구조화에 초점을 두며, ACT는 인지적 탈융합과 경험의 수용을 제시하는 차이점도 있다. 그러나 궁극적으로 두 이론은 왜곡된 인지에서 비롯된 부적응적 정서에서 벗어나 자신, 타인, 세상에 대해 무조건적 수용의 자세를 갖고 가치를 향해 삶을 살아갈 것을 촉구한다. 본 연구는 드물게 연구된 REBT와 ACT의 비교 연구라는 점에 의의가 있으나 다소 포괄적인 주제를 가지고 있다는 한계점이 있다. 이러한 한계를 딛고 삶의 수용이라는 공통된 목표를 가지고 있는 REBT와 ACT의 이론을 절충하고 통합하여 인간의 부적응적 행동을 개선할 수 있는 보다 효과적인 치료 방안 및 효과 검증의 후속 연구를 제안해 본다. The purpose of this study is to present the theoretical basis for the causes of human maladaptive behavior and solutions through an integrated review of Rational Emotive Behavior Therapy (REBT) and Acceptance & Commitment (ACT). . To this end, a literature study was conducted to compare and analyze the definitions, human views, main concepts, counseling processes, and techniques of the two counseling theories to lay a theoretical foundation for the causes of human maladaptation and countermeasures. As a result of the study, it was discovered that REBT and ACT have a common view that the combination of language and cognitive structure causes maladaptive emotions and behaviors. As a solution to maladaptive emotions and behaviors formed by distorted cognition, REBT focuses on cognitive restructuring, while ACT also proposes cognitive defusion and acceptance of experience. However, ultimately, both theories urge us to break away from maladaptive emotions resulting from distorted cognition and live our lives toward values with an attitude of unconditional acceptance of ourselves, others, and the world. This study is significant in that it is a comparative study between REBT and ACT, which has been rarely studied, but has a limitation in that it has a rather comprehensive topic. By overcoming these limitations and compromising and integrating the theories of REBT and ACT, which have a common goal of accepting life, we propose a more effective treatment plan that can improve maladaptive human behavior and follow-up research to verify effectiveness.

A comparison between prenatal ultrasound and fetal MR Imaging in Life-threatening diffuse neonatal hemangiomatosis (DHN) complicated with Kasabach-Merritt-syndrome

곽세현 ( Se Hyoun Kwak ),Se Kyung Choi,Jeong Su Choi,Yeun Hee Kim,Ki Chul Kil,Gui Se Ra Lee,Sa Jin Kim,Hyun Young Ahn,Jong Chul Shin 대한산부인과학회 2008 대한산부인과학회 학술대회 Vol.94 No.-

ATM-PON 시스템에서 MAC 프로토콜의 성능평가

최세라(Se-Ra Choi),장종욱(Jong-Wook Jang),김진일(Jin-Il Kim) 한국멀티미디어학회 1999 한국멀티미디어학회 학술발표논문집 Vol.1999 No.2

Effect of Nb Doping on Chemical Sensing Performance of Two-Dimensional Layered MoSe₂

Choi, Sun Young,Kim, Yonghun,Chung, Hee-Suk,Kim, Ah Ra,Kwon, Jung-Dae,Park, Jucheol,Kim, Young Lae,Kwon, Se-Hun,Hahm, Myung Gwan,Cho, Byungjin American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.4

<P>Here, we report that Nb doping of two-dimensional (2D) MoSe2 layered nanomaterials is a promising approach to improve their gas sensing performance. In this study, Nb atoms were incorporated into a 2D MoSe2 host matrix, and the Nb doping concentration could be precisely controlled by varying the number of Nb2O5 deposition cycles in the plasma enhanced atomic layer deposition process. At relatively low Nb dopant concentrations, MoSe2 showed enhanced device durability as well as NO2 gas response, attributed to its small grains and stabilized grain boundaries. Meanwhile, an increase in the Nb doping concentration deteriorated the NO2 gas response. This might be attributed to a considerable increase in the number of metallic NbSe2 regions, which do not respond to gas molecules. This novel method of doping 2D transition metal dichalcogenide-based nanomaterials with metal atoms is a promising approach to improve the performance such as stability and gas response of 2D gas sensors.</P>

Accelerated degradation characterization using NaOH solution with respect to porosity and pore size of salt-leaching scaffold

Se-Hwan Lee,Ki Myoung Song,A Ra Jo,Chang Hee Woo,Ghi Pyoung Choi,Young-Sam Cho 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.4

Poster Session : PS 0894 ; Lower GI Tract : Total Colonic Decompression after Colonoscopy Decreases Post-Colonoscopy Abdominal Pain: A Randomized Double-Blind Controlled Trial

( Se Woo Park ),( Won Joong Jeon ),( Jin Dong Kim ),( Sang Jin Lee ),( A Ra Choi ),( Ban Seok Lee ),( Jin Lee ),( Dong Hee Koh ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

Background: Abdominal pain that occurs after a colonoscopy may cause significant discomfort in some patients, and residual bowel gas is thought to be a key contributor to this abdominal pain. The purpose of this study was to determine whether total colonic decompression after colonoscopy decreased post-colonoscopy abdominal pain. Methods: Asymptomatic 300 patients who underwent colonoscopy under sedation were randomized to either the decompression group or the control group. Initial colonoscopic procedure was performed uniformly in both groups. After the colonoscopy examination was completed, the colonoscope was reinserted into the cecum, and the intraluminal air was aspirated during withdrawal in the decompression group. Abdominal pain was assessed before discharge and 24-48 hours after colonoscopy using a 10-point visual analogue scale (VAS). Results: The two groups were similar with regard to clinical, demographic and procedural factors. Among 288 patients, the incidence of abdominal pain (VAS =1) after colonoscopy was 38 (26.6%) of 143 patients in the decompression group and 95 (65.5%) of 145 patients in the control group (VAS 0.68 ± 1.35 vs. 2.14 ± 2.15, P <0.001). There was an 86.1% reduction rate of abdominal pain by colonic decompression, based on multivariate analysis (Odds ratio 0.139 [0.077-0.250], P <0.001). Furthermore, independent factors for abdominal pain included female gender and total duration of procedure longer than 800 seconds. There were no reinsertion-related complications in the decompression group. Conclusions: Total colonic decompression after colonoscopy has a beneficial effect and can reduce post-colonoscopy abdominal pain without additional complications.

대장균에서 무작위 샤인-달가노 서열이 소성장호르몬 유전자 발현에 미치는 영향

나경수,백형석,이용세,최장원 부산대학교 유전공학연구소 2000 분자생물학 연구보 Vol.16 No.-

소성장호르몬 유전자를 대장균에서 발현시키기 위하여 외부 유전자 발현에 중요한 요인중의 하나인 해독과정의 효율성을 증가시킬 수 있는 즉 mRNA의 이차구조를 풀어주는 적절한 Shine-Dalgarno (SD) 서열을 찾기 위하여 SD와 ATG 코돈 사이의 거리를 9 base로 고정하고 random DNA 서열로 oligonucleotide를 합성하여 소성장호르몬 유전자 앞쪽에 넣어 줌으로서 mRNA 이차구조의 변형에 의한 소성장호르몬 단백질의 발현에 미치는 영향을 조사하였다. 발현벡터들은 T7 프로모터를 갖는 pT7-1 벡터를 이용하여 제조하였고, positive 클론들은 colony hybridization과 DNA 크기에 의해 선별되었으며, 얻어진 클론들은 pT7A 또는 pT7B 계열의 플라스미드로 명명되었다. DNA 염기분석에 의해 소성장호르몬 유전자와 여러 가지 SD 서열을 갖는 19 클론을 선별하였고, E. coli BL21(DE3) 균주에서 단백질 발현을 유도하여 western blot에 의해 분석하였을때, 낮은 양이지만 모든 클론들이 소성장호르몬을 생성하였다. 그러나 SD 서열 및 SD-ATG 사이으 염기서열들은 bGH 발현에 큰영향을 주지 못하였다. 이는 대장균에서 bGH의 발현의 경우 bGH mRNA codon 1번부터 5번 사이에 형성되는 이차구조를 파괴시키는 것이 발현 조절에 중요 인자인 것으로 나타났다. In order to search for the effects of Shine-Dalgarno (SD) sequence and nucleotide sequence of spacer region (SD-ATC) on bGH expression, oligonucleotides containing random SD sequences and a spacer region were chemically synthesized. The distance between SD region and initiation codon (ATG) was fixed to 9 nucleotides in length. The expression vectors have been constructed using pT7-1 vector containing a T7 promoter. Positive clones were screened with colony hybridization and named pT7A ro pT7B plasmid series. The selected clones were confirmed by DNA sequencing and finally, 19 clones having various SD combinations were obtained. When bovine growth hormone was induced by IPTG in E. coli BL21(DE3), all cells harboring these plasmids produced a detectable level of bGH in western blot analysis. However, various SD sequences did not affect on bGH expression, indicating that the sequences of SD and the spacer region did not sufficiently destabilize mRNA secondary structure of bGH gene. Therefore, these results indicate that the disruption of mRNA secondary structure might factor regulating bGH expression in the translational initiation process.