제어기 공용화를 위한 LED 헤드램프 제어용 플랫폼 통합제어기 개발

박충섭(Choongseob Park),박동서(Dongseo Park),이은정(Eunjung Lee),김대현(Daehyun Kim),손유진(Yoojin Son),최윤석(Yunsuk Choi4),박상현(Sanghyun Park),문주환(Juwhan Moon),노태선(Taesun Rho),강소정(Sojeong Kang),이동주(Dongju Lee),김영수(You 한국자동차공학회 2018 한국자동차공학회 부문종합 학술대회 Vol.2018 No.6

For the LED front lamp system, Universal Controller is gradually getting expanded in the world. For corresponding the technical trend and system optimization, we have approached in terms of vehicle level as well as LED load level. By understanding lamp system architecture and hardware functional distribution, we could make discrete LDMs into Universal LDM based on CAN communication. It enables us to control LED lamp very flexible and scalable with regardless of lamp variation depend on regional and specified option. Additionally, it is very compatible with future technologies such as pixel and matrix control in connection with autonomous driving.

Development of a New Method based on a 3D Hand Gesture Taxonomy for Analyzing User-Preferred Gestures

Eunjung Choi,Bora Kang,Mingyu Lee,Seungjae Oh,Heejin Kim,Dong yeong Jeong,Hanul Bang,M. K. Chung,S. H. Han 대한인간공학회 2014 대한인간공학회 학술대회논문집 Vol.2014 No.5

Recent studies in gesture interfaces have focused on enhancing the naturalness of gesture vocabularies by utilizing users’ experiences related to a command. However, the previous studies lack methods for organizing the user-defined gestures in a systematic manner. It is difficult to identify the important characteristics of the user-defined gestures for commands. The users’ intentions of deriving a specific gesture for a command could be misinterpreted by the researchers. We propose a three-dimensional hand gesture taxonomy to resolve these issues. Further, we organized the user-preferred gestures that were acquired via two experiments. By subdividing the elements of each gesture, we were able to develop a new method for analyzing the important characteristics of gestures. This study proposes a novel and systematic approach to quantifying user-preferred gestures.

Onboard Software Development and Performance Assessment of Enhanced Spaceborne GPS Receiver for Small Satellite System

Eunjung Choi,Jun Young Park,Hungu Lee,Sang Young Park,Kyu Hong Choi 한국항공우주학회 2008 한국항공우주학회 학술발표회 논문집 Vol.- No.-

The spaceborne GPS receiver is one of the indispensable payloads for the high-resolution earth observation satellites. In this paper, the onboard software architecture, implementation and test results as well as the hardware system related to the on board software are described. The hardware design is mainly built with the 12 channel Ll C/A code baseband correlator and 32-bit floating-point DSP microprocessor. The onboard software architecture is designed using DSP/BIOS to support the real-time multitasking operating system. The on board software of the enhanced spaceborne GPS receiver contains the task scheduling, the algorithms of GPS signal baseband processing, satellite ephemeris calculations and real-time orbit determination. The performance test is based on hardware-in-the-loop simulations using GPS simulator. The experimental results show that implemented software gives the fast TTFF and stable tracking of GPS SV. In the event, the enhanced spaceborne GPS receiver is able to provide the position and velocity stably.

Three Dimensional Hand Gesture Taxonomy for Commands

Eunjung Choi,Donghun Lee,Min K. Chung 대한인간공학회 2012 大韓人間工學會誌 Vol.31 No.4

Objective: The aim of this study is to suggest three-dimensional(3D) hand gesture taxonomy to organize the user"s intention of his/her decisions on deriving a certain gesture systematically. Background: With advanced technologies of gesture recognition, various researchers have studied to focus on deriving intuitive gestures for commands from users. In most of the previous studies, the users" reasons for deriving a certain gesture for a command were only used as a reference to group various gestures. Method: A total of eleven studies which categorized gestures accompanied by speech were investigated. Also a case study with thirty participants was conducted to understand gesture-features which derived from the users specifically. Results: Through the literature review, a total of nine gesture-features were extracted. After conducting the case study, the nine gesture-features were narrowed down a total of seven gesture-features. Conclusion: Three-dimensional hand gesture taxonomy including a total of seven gesture-features was developed. Application: Three-dimensional hand gesture taxonomy might be used as a check list to understand the users" reasons.

A Notation Method for Three Dimensional Hand Gesture

Eunjung Choi,Heejin Kim,Min K. Chung 대한인간공학회 2012 大韓人間工學會誌 Vol.31 No.4

Objective: The aim of this study is to suggest a notation method for three-dimensional hand gesture. Background: To match intuitive gestures with commands of products, various studies have tried to derive gestures from users. In this case, various gestures for a command are derived due to various users" experience. Thus, organizing the gestures systematically and identifying similar pattern of them have become one of important issues. Method: Related studies about gesture taxonomy and notating sign language were investigated. Results: Through the literature review, a total of five elements of static gesture were selected, and a total of three forms of dynamic gesture were identified. Also temporal variability(reputation) was additionally selected. Conclusion: A notation method which follows a combination sequence of the gesture elements was suggested. Application: A notation method for three dimensional hand gestures might be used to describe and organize the user-defined gesture systematically.

Polymer Thin Film–Induced Tumor Spheroids Acquire Cancer Stem Cell–like Properties

Choi, Minsuk,Yu, Seung J.,Choi, Yoonjung,Lee, Hak R.,Lee, Eunbeol,Lee, Eunjung,Lee, Yumi,Song, Junhyuk,Son, Jin G.,Lee, Tae G.,Kim, Jin Y.,Kang, Sukmo,Baek, Jieung,Lee, Daeyoup,Im, Sung G.,Jon, Sangyo American Association for Cancer Research 2018 Cancer Research Vol.78 No.24

<P>A new cell culture technology enables highly tumorigenic 3D spheroids to be easily generated from various cancer cell sources in the common laboratory.</P><P><B></B></P><P>Although cancer stem cells (CSC) are thought to be responsible for tumor recurrence and resistance to chemotherapy, CSC-related research and drug development have been hampered by the limited supply of diverse, patient-derived CSC. Here, we present a functional polymer thin film (PTF) platform that promotes conversion of cancer cells to highly tumorigenic three-dimensional (3D) spheroids without the use of biochemical or genetic manipulations. Culturing various human cancer cells on the specific PTF, poly(2,4,6,8-tetravinyl-2,4,6,8-tetramethyl cyclotetrasiloxane) (pV4D4), gave rise to numerous multicellular tumor spheroids within 24 hours with high efficiency and reproducibility. Cancer cells in the resulting spheroids showed a significant increase in the expression of CSC-associated genes and acquired increased drug resistance compared with two-dimensional monolayer-cultured controls. These spheroids also exhibited enhanced xenograft tumor-forming ability and metastatic capacity in nude mice. By enabling the generation of tumorigenic spheroids from diverse cancer cells, the surface platform described here harbors the potential to contribute to CSC-related basic research and drug development.</P><P><B>Significance:</B></P><P>A new cell culture technology enables highly tumorigenic 3D spheroids to be easily generated from various cancer cell sources in the common laboratory.</P>

Development of SS-AG20-loaded Polymeric Microparticles by Oil-in-Water (o/w) Emulsion Solvent Evaporation and Spray Drying Methods for Sustained Drug Delivery

Eunjung Choi,Cheng Zhe Bai,Areum Hong,박종상 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.10

Controlled drug delivery systems employing microparticles offer lots of advantages over conventional drug dosage formulations. Microencapsulation technique have been conducted with biodegradable polymers such as poly(lactic-co-glycolic acid) (PLGA) and poly(lactic acid) (PLA) for its adjustable biodegradability and biocompatibility. In this study, we evaluated two techniques, oil-in-water (o/w) emulsion solvent evaporation and spray drying, for preparation of polymeric microparticles encapsulating a newly synthesized drug, SSAG20, for the long-term drug delivery of this low-molecular-weight drug with a very short half-life. Drugloaded microparticles prepared by the solvent evaporation method showed a smoother morphology; however, relatively poor encapsulation efficiency and drastic initial burst were discovered as drawbacks. Spray-dried drug-loaded microparticles had an imperfect surface with pores and distorted portions so that its initial burst was critical (70.05-87.16%) when the preparation was carried out with a 5% polymeric solution. By increasing the concentration of the polymer, the morphology was refined and undesirable initial burst was circumvented (burst was reduced to 35.93-74.85%) while retaining high encapsulation efficiency. Moreover, by encapsulating the drug with various biodegradable polymers using the spray drying method, gradual and sustained drug release, for up to 2 weeks, was achieved.

Color Change of Esthetic Restorative Materials for Different Staining and Whitening Dentifrices

( Eunjung Choi ),( Hyeonsoo Jang ),( Yelim Seo ),( Youngju Kim ),( Gayoung Lee ),( Youlim Kim ),( Soo-jeong Hwang ) 한국치위생과학회 2021 치위생과학회지 Vol.21 No.3

Background: As the importance of the esthetic function of teeth increases, the use of esthetic restoration materials and whitening treatment are increasing. The purpose of this study was to investigate the color change of esthetic restoration materials upon using staining and whitening toothpaste. Methods: Light curing (LC) packable composite resin, LC flowable resin, LC glass ionomer (GI), and self-curing GI specimens were colored in coffee or curry for three hours a day for seven days. After that, regular toothpaste, whitening toothpaste containing hydrogen peroxide, and whitening toothpaste containing activated charcoal were applied for three minutes three times a day for two weeks. Luminosity (L), chromaticity a (a), and chromaticity b (b) were measured using a spectrophotometer once a week. Results: In the coffee-colored group, the change in L²*a²*b² (E²) with time was significant (p=0.004), there was no difference for different toothpaste types (p=0.646), and there was significant difference (p<0.001) for different esthetic restorative materials. The change of E² in the curry-colored group was significant only for different esthetic restorative materials (p<0.001). In the coffee-colored group, the L, a, and b values of the light-curing GI showed greater change than other materials after staining and one week after whitening, turning dark, red, and yellow. In the curry-colored group, L did not differ for different materials and times, and a and b showed the greatest difference in light-curing GI after staining and one and two weeks after whitening. Conclusion: The use of whitening toothpaste for two weeks was not different from the use of general toothpaste in the removal of staining or whitening. Since light-curing GI is the most vulnerable to coloration, it is recommended that coloring by food chromogen should be explained in advance, before using light-curing GI for teeth restoration.

Phaeophyta Extracts Exhibit Antiviral Activity against Feline Calicivirus

Choi, Yuri,Kim, Eunjung,Moon, Sunyoung,Choi, Jong-Duck,Lee, Myung-Suk,Kim, Young-Mog The Korean Society of Fisheries and Aquatic Scienc 2014 Fisheries and Aquatic Sciences Vol.17 No.1

The objective of this study was to evaluate the antiviral activity of Phaeophyta extracts against feline calicivirus (FCV), used as a norovirus surrogate. A bioassay-guided cytotoxicity and virus infectivity assay revealed that methanolic extracts of Phaeophyta possessed significant antiviral activity against FCV. Among them, Eisenia bicyclis extract exhibited the highest antiviral activity against FCV. The 50% effective concentration of the extract ($EC_{50}$) inhibiting FCV viral replication by 50% was $80{\mu}g/mL$. The extract also showed the highest selectivity index, calculated from the ratio of the median cellular cytotoxicity concentration ($CC_{50}$) and $EC_{50}$, indicating antiviral efficacy against FCV. In addition, significant interruption of FCV infection was observed by pretreatment of host Crandall-Reese feline kidney cells with the E. bicyclis extract ($200{\mu}g/mL$) prior to virus infection, in a dosedependent manner.

Perceptions of Political Corruption and Voting Behavior in South Korea

Eunjung Choi 이화여자대학교 국제통상협력연구소 2019 Asian International Studies Review Vol.20 No.2

While regular and competitive elections are expected to lower political corruption by holding elected officials accountable for their actions, citizens often fail to vote corrupt officials out of office in elections. This article explores how citizens’ perceptions of political corruption influence their voting behavior by testing three competing theories: nonvoting, opposition voting, and corruption voting. This study also investigates the types of voters involved in each form of voting by considering three mediating factors: economic evaluation, partisanship, and education. Empirical findings from the South Korean case suggest that, in general, the high level of perceived corruption decreases voter turnout, confirming the nonvoting theory. Second, corruption voting occurs mostly among those who positively evaluate the economy and have the same partisan affiliation as the incumbent candidate. Finally, a high level of education leads to opposition voting. In sum, the empirical evidence confirms that incumbent candidates’ and party’s political corruption does not always lead to the electoral victory of opposition parties and their candidates because the mediating factors play a role in strengthening or weakening the patterns of nonvoting, opposition voting, and corruption voting.