디지털 컨버전스에서의 인터럽션: 멀티 모달리티와 멀티 태스킹 간의 상호 관계를 중심으로

이기호,정승기,김혜진,이인성,김진우,Lee, Ki-Ho,Jung, Seung-Ki,Kim, Hye-Jin,Lee, In-Seong,Kim, Jin-Woo 대한인간공학회 2007 大韓人間工學會誌 Vol.26 No.3

Digital convergence, defined as the creative fusion of once-independent technologies and service, is getting more attention recently. Interruptions among internal functions happen frequently in digital convergence products because many functions that were in separate products are merged into a single product. Multi-tasking and multi-modality are two distinctive features of interruption in digital convergence products, but their impacts to the user have not been investigated yet. This study conducted a controlled experiment to investigate the impacts of multi-tasking and multi-modality on the subjective satisfaction and objective performance of digital convergent products. The study results indicate that multi-tasking and multi-modality have substantial effects individually as well as together. The paper ends with practical and theoretical implications of study results as well as research limits and future research.

K⁺ 통로 조절 약물이 마우스 골격근의 피로현상에 미치는 영향

이기호,류판동,이문한,이항,Lee, Ki-ho,Ryu, Pan-dong,Lee, Mun-han,Lee, Hang 대한수의학회 1995 大韓獸醫學會誌 Vol.35 No.2

The density of ATP-sensitive potassium($K_{APT}$) channels, that open as intracellular ATP concentration falls below a critical level, is very high in skeletal muscle surface membrane and those high density may imply that $K_{ATP}$ channels have very important physiological roles. To elucidate a role of $K_{ATP}$ in relation to fatigue, the modulating effects of potassium channel openers and blockers on the fatigue velocity(FV) of mouse extensor hallucis longus muscle(EHL) were investigated in vitro. Twitch contraction was induced by an electrical field stimulation (EFS: 24-48V, 20ms, 0.2-4Hz) and resulting contraction force was isometrically recorded. The twitch forces were gradually decreased to 25% of initial contraction force(ICF) in $37.52{\pm}1.55sec$($mean{\pm}s.e.m.$, n=135), indicating the fatigue phenomena. The mean velocity for development of the fatigue was measured during the period that twitch force decreased to half($FV_{0/0.5}$) and during the period from half to 25%($FV_{0.5/0.25}$) of ICF. The fatigue was induced once every one hour and the tissue response was stable for up to 4 hours. In control condition, ICF was $5.8{\pm}0.12g$ (n=144) and decreased to 50% of ICF with the mean fatigue velocity of $0.182{\pm}0.006g/sec$($FV_{0/0.5}$, n=135) and from 50% to 25% of ICF with $0.084{\pm}0.004g/sec$($FV_{0.5/0.25}$, n=135). Cromakalim($50{\mu}M$) significantly increased $FV_{0.5/0.25}$(n=4). Glibenclamide($IC_{50}>50{\mu}M$), $Ba^{2+}$($IC_{50}=10{\mu}M$), 4-aminopyridine($FV_{0/0.5}$, $IC_{50}=0.5mM$; $FV_{0.5/0.25}$, $IC_{50}=2mM$) decreased both $FV_{0/0.5}$ and $FV_{0.5/0.25}$ concentration-dependently up to 75%. $TEA^+$(30mM), E-4031($10{\mu}M$), tolbutamide(1mM) decreased $FV_{0.5/0.25}$, but apamin(300nM) and $TEA^+$(10mM) showed no significant effects. Our results suggest that activation of the $K_{ATP}$ channels may be major cause of $K^+$ outflux during development of the fatigue and the isolated EHL muscle could be an useful experimental preparation in studying the fatigue phenomena in skeletal muscle. In addition, the possibility of activation of delayed rectifier during the fatigue development remains to be studied further.

Clinical Efficacy of Latex Cover for Dental Handpiece

이기호,백동헌,Lee, Ki-Ho,Paek, Dong-Heon Korean Academy of Orofacial Pain and Oral Medicine 2009 Journal of Oral Medicine and Pain Vol.34 No.3

The purpose of this study was to investigate the clinical efficacy of latex cover developed for dental handpiece on contamination of microorganisms during dental treatment and to determine whether it can be an alternative to conventional sterilization such as autoclaving. E. fecaelis was used as a experimental microorganism instead of oral flora. Experimental bowl with 2 cm of rectangular cavity was fabricated for handpiece operating instead of oral cavity. Latex covers ($Orokeeper^{(R)}$, Orobiotech Co., Korea) and several handpieces were used after sterilization by autoclave. Four experiments were performed to evaluate bacterial contamination related with (1) various parts of dental handpiece, (2) swabbing time with alcohol sponge, (3) postoperative air-water spraying time and (4) consecutive use of latex covers without autoclaving. The results show that face of handpiece uncovered with latex cover was severely contaminated than the covered area and that most bacteria were removed by swabbing face and head area of dental hand-piece and by air-water spraying more than 15 seconds nearly up to the level of sterilization. Conclusively it can be suggested that use of latex cover for handpiece during dental procedure, swabbing with alcohol sponge is air-water spraying for more than 15 seconds after use of dental handpiece should be very useful and practical for prevention of cross infection and should be an alternative method for the sterilization of dental handpiece under some difficult situations not being able to sterilize a handpiece with autoclave.

제주시 지역 미세먼지의 변동과 화학적 구성 특성

이기호,김수미,김길성,허철구,Lee, Ki-Ho,Kim, Su-Mi,Kim, Kil-Seong,Hu, Chul-Goo 한국환경과학회 2020 한국환경과학회지 Vol.29 No.5

This study investigated the nitrate formation process, and mass closure of Particulate Matter (PM) were calculated over the urbanized area of Jeju Island. The data for eight water-soluble inorganic ions and nineteen elements in PM_2.5 and PM₁₀ were used. The results show that the nitrate concentration increased as excess ammonium increased in ammonium-rich samples. Furthermore, nitrate formation was not as important in ammonium-poor samples as it was in previous studies. According to the sum of the measured species, approximately 45~53% of gravimetric mass of PM remained unidentified. To calculate the mass closure for both PM_2.5 and PM₁₀, PM chemical components were categorized into secondary inorganic aerosol, crustal matter, sea salt, trace matter and unidentified matter. The results by the mass reconstruction of PM components show that the portion of unidentified matter was decreased from 52.7% to 44.0% in PM_2.5 and from 45.1% to 29.1% in PM₁₀, despite the exclusion of organic matter and elemental carbon.

제주시 도로변에서의 에어로졸의 입경별 분포 특성

이기호,김수미,허철구,Lee, Ki-Ho,Kim, Su-Mi,Hu, Chul-Goo 한국환경과학회 2021 한국환경과학회지 Vol.30 No.9

Measurements on mass size distribution of roadside aerosols were obtained in downtown Jeju City from July 2018 to May 2020 using an 8-stage cascade impactor sampler and the compositions of aerosols were analyzed. The mass size distribution of total aerosols was bimodal with aerosols existing in both the fine and coarse modes. The mass size distributions of Na⁺, Mg²⁺, Ca²⁺, Cl^-, NH₄⁺ and SO₄^2- were unimodal, whereas that of K⁺ was bimodal. For NO₃^-, the size distribution in winter and spring was bimodal with the peaks in both fine and coarse modes, whereas for summer and autumn the distribution was unimodal with a peak in the coarse mode. NH₄⁺ was found to co-exist with SO₄^2- in the fine mode with an average molar ratio of [NH₄⁺]/[SO₄^2-] equal to 2.05. Good correlation was observed between NO₃^- and NH₄⁺ in the fine mode particles in spring and winter. Based on the value of the marine enrichment factor for Cl^-, Mg²⁺, K⁺, Ca²⁺ and SO₄^2-, it may be inferred that a major part of the roadside aerosols in downtown Jeju City was largely contributed by terrigenous sources, although the influence of sea salt was normally present.

Application of Synchrotron Radiaton to Semiconductor Process and Surface Photochemical Reaction

이기호,김병엽,이시우,Lee, Ki-Ho,Kim, Byoung-Youp,Rhee, Shi-Woo 한국진공학회 1995 Applied Science and Convergence Technology Vol.4 No.s1

ARM7 호환 32 - Bit RISC Microprocessor 설계

이기호(Ki-Ho Lee),유영재(Young-Jae Yoo),김기민(Ki-Min Kim),강용호(Yong-Ho Kang),송호준(Ho-Jun Song),이철훈(Cheol-Hoon Lee) 한국정보과학회 1998 한국정보과학회 학술발표논문집 Vol.25 No.2Ⅲ

본 논문에서는 RISC Microprocessor Core 설계에 대한 기반 기술을 확립하며, GPS(Global Positioning System)같은 Embedded 시스템 등에서 주로 사용되어 지고 있는 ARM사의 ARM7 CPU와 이진 호환이 가능한 Microprocessor를 설계하고자 하였다. 이를 위하여 RISC Microprocessor의 기본적인 구조를 바탕으로 하여 ARM7 CPU와의 호환을 위해서 ARM7 CPU 의 명령어들이 주어진 Clock안에 수행될 수 있도록 설계를 하였고, 여러 모듈들을 원활히 공유할 수 있도록 내부에 공유 버스를 설계하였다. 설계를 위해서 Verilog-HDL(Hardware Description Language)을 사용하였으며, Microprocessor를 기술하는데 있어서 Behavioral 구조와 RTL(Register Transfer Level) 구조를 혼합하여 사용하였다. 설계된 Microprocessor의 동작은 면적과 타이밍의 최적화를 거친 후 Cwaves 툴을 사용하여 실직적인 ARM7의 명령어들을 수행하면서 검증하였다.

프로그래밍 언어 교육용 ITS에서의 트레이스 시각화

이기호(Ki-Ho Lee),오율하(Yul-Ha Oh) 한국정보과학회 1996 정보과학회논문지(B) Vol.23 No.4

본 논문은 프로그램의 실행 시간 오류 교정을 위한 트레이스 시각화 시스템인 TRAVIS(TRAce VIsualization System)를 구축하여 C 프로그래밍 언어를 주제 영역으로 하는 지능형 교육 시스템(ITS: Intelligent Tutoring System)에서 학습자 스스로 오류 발생을 인지하고 발생 원인을 파악한 후, 문제를 해결할 수 있도록 함으로써 학습자에게 주체적인 디버깅 능력을 부여하는데 그 목적을 두고 있다. TRAVIS는 프로그램이 실행되는 매 단계마다 제어의 흐름과 선언된 모든 변수들의 바인딩 값을 시각적으로 표현하는 트레이스 환경을 제공함으로써, 학습자로 하여금 프로그램의 동적 메카니즘을 쉽게 이해하도록 하며 이를 바탕으로 실행 시간 오류의 원인을 발견하고 수정할 수 있는 문제 해결 능력을 습득하는 학습에 대한 기초를 마련한다. In this thesis, we build the TRAce VIsualization System(TRAVIS) to recover run-time errors in program, and pursue the ultimate goal of making students cultivate their abilities which Identify the error occurring, find what is the reason, and then cure the problems in program. TRAVIS makes students understand dynamic mechanism easily, by providing trace environment which visually expresses the flow of control to each step of executing program and the binding values of all declared variables. With this, students can cultivate their abilities to find the reasons of errors and correct them by themselves.

굴패각 혼합토의 압밀 및 투수특성

이기호(Lee Ki-Ho),한종옥(Han Jong-Ok) 대한토목학회 2001 대한토목학회논문집 C Vol.21 No.4

인체 멜라닌 세포의 배양에 관한 연구

이기호(Ki Ho Lee),이무형(Mu Hyoung Lee),박재경(Jai Kyung Park),허충림(Choong Rim Haw) 대한피부과학회 1990 대한피부과학회지 Vol.28 No.2

The author evaluated the optimal concentration of 3 compositions of TIC medium which has used as the melanacytes culture medium. The concentrations of placental extract and bovine pituitary extract, which have the ability to promote proliferation of melanocytes, were evaluated also. Modified TIC medium with above 5 components of evaluated concentration was very effective in melanocytes culture. The results were as follows : l. 12-0-tetradecanoyl-phorbol-13-acetate (TPA) showed effective melanocytes proliferating activity at the concentration of 30ngml (p(0.05) 2. Isobutylmet:hyl xanthine (IBMX) showed effective melanocytes proliferating activity at the concentration of 0.3mM (p(0.05) 3. Cholera toxin (CT) showed effective melanocytes proliferating activity at the concentration of )OnM (p(0.05) 4. Two percentages of placental extract in culture medium showed effective melanocytes proliferating activity. S. Two percentages of bovine pituitary extract in culture medium showed effective melanocytes proliferating activity. 6. Placental extract and isobutylmethyl xanthine proved to have high melanocytes proliferating activity. 7. Melanocytes proliferated rapidly on modified TIC medium (Proliferation doubling time . about 43 hours) 8. The peak time of melanocytes proliferation (7.2 X 10/cm) was observed on the seventh day of culture, From this data, this culture system can be recommended as a new melanocytes culture. (Kor J Dermatoi 28<2): 136 146, 1990)