Pade 近似化 方法에 依한 필터의 設計

郭勳星,金英百 全北大學校 1981 論文集 Vol.23 No.-

A rational approximation procedure for digital filter design is presented in this paper. More specially, an explicit expression for the designed filter transfer function can be obtained once a rational approximation for the analytic part of the Fourier series expansion of the desired filter characteristic is determined. To demonstrate the efficiency of this technique, we derive a two-sided Pade´ approximation from the one-sided Pade´ approximant. Two examples are given to illustrate this design procedure.

분류나무와 결측치

곽영훈,김지현 崇實大學校 生産技術硏究所 2001 論文集 Vol.31 No.-

There are many statistical method for classification or discriminant analysis. The classification tree is one of them. There are several algorithms for classification tree. In this paper a comparison study is done of the performance of those algorithms for classification tree when we have missing values in predictors at hand. With the misclassification error rate as a performance measure, different algorithms are compared for different patterns of missing values.

이러닝에서의 학습자 정보 표준화 모형 연구

정영란,곽덕훈 한국컴퓨터교육학회 2004 컴퓨터교육학회 논문지 Vol.7 No.4

학습자 정보의 표준화는 원격교육기관간의 원활한 학습자 정보 교류와 학습자 정보의 체계적 관리를 통한 학습자 중심의 이러닝 서비스를 제공하기 위해 반드시 필요하다. 기존의 학습자 정보 표준화 모형은 시스템간의 교류에 중점을 두는 경향이 있었으나, 학습자의 개별 특성에 따른 맞춤식 교육을 위해서는 교육적 관점에서 학습자 정보의 표준화를 다룰 필요가 있다. 이를 위해 본 연구에서는 학습자 정보 표준화 모형에 대한 선행 연구를 바탕으로 학습자 성향 정보와 학습 성과 정보등 교육적 목적을 위한 구체적인 표준화 항목을 도출하여, 전체 3개 영역의 33개 항목으로 구성된 학습자 정보 표준화 모형을 개발하였다. 또한 이러닝의 운영 경험이 있는 26개 대학을 대상으로 설문조사를 실시하여 학습자 정보 표준화 모형을 위한 필수 정보와 선택 정보를 구분하였다. 표준화 모형은 그 적용 범위와 목적에 따라 각 요소들의 중요도가 달라지는데, 본 연구에서는 표준화 모형의 적용 범위를 대학을 중심으로 한 고등교육 영역으로 한정하였다. The standardization of learner information is needed for exchanging learner information in e-learning system with another educational institution. And also it is needed for providing customized educational service to the learner's characteristics. The purpose of this study is to develop standardization model of learner information that is focused learner's characteristics and performance in higher educational situation. Earlier researches related to the standardization of learner information are analyzed and added some ideas from instructional theory for dealing with meaningful information about learners. The draft standardization model of learner information with 33 of items in 3 areas is proposed. For the validation of this model proposed, we surveyed from 26 of universities that have been experienced e-learning service. It was divided into mandatory and optional items to the result of the survey.

ZnO:AI 과 ITO 투명전도막을 이용한 플랙시블 DSCs의 변환효율 특성

정기영,김지훈,성열문,곽동주,추영배 경성대학교 공학기술연구소 2010 공학기술연구지 Vol.16 No.-

In order to investigate the possible application of ZnO films as a transparent conducting oxide (TCO) electrode for film-typed dye sensitized solar cell(F-DSC), ZnO:Al films were prepared by RF magnetron sputtering method. The effects of gas pressure on the structural and electrical properties of ZnO films were mainly studied experimentally. F-DSC using either a ZnO:Al or indium tin oxide (ITO) electrode were also fabricated separately under the same manufacturing conditions. The electro-optical conversion efficiency and fill factor of the F-DSCs using both ZnO:Al and ITO transparent conducting electrodes were measured and compared with each other. ZnO:Al films showed the minimum resistivity of 2.6 x10^(-3)Ω-cm and a transmittance of 91.7% under the experimental conditions of doping concentration of 2 wt% of Al₂0₃ and gas pressure of 5mTorr. ITO films fabricated at 5mTorr of gas pressure also showed the minimum resistivity of 1.5x10^(-3)Ω-cm and transmittance of 92.1%. Although the electrical resistivity of ZnO:Al is higher than that of ITO, the conversion efficiency of F-DSC using ZnO:Al was comparable with that of F-DSC using ITO. The conversion efficiency of F-DSCs using ZnO:Al and ITO electrodes are about 2.8% and 2.9%, respectively.

고정밀 연삭기용 주축시스템 설계

편영식,이건범,박정현,요꼬이 요시유끼,여진욱,안건준,곽철훈 한국공작기계학회 2003 한국생산제조학회지 Vol.12 No.3

Any one of the high precision spindle systems and guide way systems, the high stiffness of structure, the error compensation during assembly, high accuracy control system is inevitable technology for development of high precision machine tools. Especially, among these, design of spindle system is one of the most important technologies leading high precision of machine tool and high quality of manufactured products. A high speed and high precision spindle system which will be used for final machining of ferrule, is designed considering the effect of heat, cutting torque, cutting force, and work-piece materials. The detailed design and analysis process are presented.

Channel stamping 법으로 전이된 Cu pattern의 형상

이영훈,곽재찬,강봉석,김희철,최병호,Lange, F.F. 國立金烏工科大學校 産業技術開發硏究院 2002 産業技術開發硏究 Vol.18 No.-

A matallo-organic solution was stamped from the channels of a polymer stamp onto a glass. The precursor solution consisted of copper 2-ethylhexanonate, 2-ethoxyethanol as a solvent and ethylene glycol to improve surface energies. The solution was deposited to the polymer stamp by spin coater. After drying the solution in channels of the stamp, the dried ink was transferred to a substrate by debonding from channels. The process parameters such as solution compositions and pressing methods were discussed experimentally to form a copper pattern whose morphology was excellent.

Systolic Array를 이용한 2차원 CMT

朴敏植,金英百,郭勳星 전북대학교 전자산업개발연구소 1990 전자산업연구 Vol.1 No.-

This paper proposes systolic array for 2-D C-Matrix Transtorm(CMT). Compared the conventional method with the proposed 2-D CMT without matrix transpolsition, it is required the more PE's, but the less latency. Also, it is shown that the systolic array VLSI implementation for 2-D CMT is feasible.

AZO 투명전도막의 전기 광학적 특성에 미치는 PET 기판 표면처리 효과

박병욱,김지훈,성열문,추영배,곽동주 경성대학교 공학기술연구소 2008 공학기술연구지 Vol.15 No.-

In this paper aluminium-doped zinc oxide(ZnO:Al) conducting layer was deposited on polyethylene terephthalate(PET) substrate by r. f. magnetron sputtering method PET substrate was modified by a DBD(dielectric barrier discharge) plasma before sputtering to improve the electric and optical properties of ZnO:Al film and to increase also the deposition rate The effect of heat treatment time on the dectrical, optical, chemical and structural properties of ZnO:Al thin film were investigated experimentally The PET films modified with the DBD plasma showed a significant decrease in water contact angle The deposition rate of ZnO:Al film in the case of the plasma-treated substrate was also increased by around 2 times compared to the untreated substrate The minimum resistivity of about 28×10-3 Ω-cm and transmittance of about 83.3% were obtained under the experimental condition of 6min of heat treatment time.

강산 및 강알칼리 음독에서 냉각 용액을 사용한 희석 요법과 중화 요법의 가능성

이중의,송형곤,김동훈,권운용,곽영호,서길준,윤여규 대한응급의학회 2001 대한응급의학회지 Vol.12 No.3

Background: There is no effective treatment modality for caustic agent ingestion. Dilution and neutralization are prohibited because of the risk of secondary thermal injury. This experiment is designed to evaluate the amount of dilution and neutralization heat and to gauge the applicability of dilution and neutralization therapy using cold solutions to suppress the peak temperature. Methods: This is an in-vitro chemical experiment. HCl, CH3COOH, NaOH, and NH4OH are selected as representatives of strong and weak acids and strong and weak alkali, respectively. 20℃, 11.6M, 5.8M, and 2.9M solutions of each acid and alkali are made and mixed using a magnetic stirrer at a room air temperature of 28℃. The peak temperature, the duration above 40℃, and the heat amount are measured or calculated. Results: When a 11.6M HCl or NaOH solution is diluted with same amount of water, 32 or 18cal. per mL of HCl or NaOH is produced, respectively. HCl produces a significant peak temperature, but NaOH does not. The lower the concentration, the lower the amount of heat production. 11.6M CH3COOH and NH4OH solutions don't produce dilution heat.11.6M and 5.8M solutions of all acids and alkali produce destructive neutralization heat. However, 2.9M solutions produce neutralization heat which might be controllable. When a 11.6M HCl or NaOH solution is neutralized with a -10℃ 2.9 M NaOH or HCl solution, respectively, the peak temperature produced is below 40℃ and seems to add little thermal damage to viable tissue. Conclusion: Dilution and neutralization with a cold solution in cases of strong acid or alkali ingestion is a promising method to avoid thermal injury.

반코마이신 내성 장내구균 분리 환자에서 황색포도알균의 내성

김동욱,신선혜,김혜진,류선,이선희,장철훈,김영대,곽임수 대한감염학회 2004 감염과 화학요법 Vol.36 No.1

목적 : Vancomycin-resistant enterococci (VRE)로부터 S. aureus로의 vacomycin 내성 유전자의 전파는 오래전부터 예견되어져 왔으며 큰 걱정거리로 남아있다. 최근에 vanA 유전자를 가지고 있는 vancomycin-resistant S. aureus 2주가 미국에서 분리되었다. 이 연구의 목적은 VRE를 보균하고 있는 환자들에서 S. aureus 보균양상과 항균제 내성을 알아보는데 그 목적이 있다. 재료 및 방법 : 2001년 1월부터 2001년 12월까지 부산대학교병원에 입원하였던 환자들 중 임상검체에서 VRE가 분리된 환자 7명과 2001년 9월부터 12월까지 외과 중 환자실에 입원하였던 환자들 중 VRE 감시배양을 시행하였던 20명의 환자들을 대상으로 하였다. 환자들은 전비공, 액와부, 회음부, 직장에서 매주 면봉으로 검체를 채취하였다. 선별배지에서 검체를 배양하여 S. aureus를 분리하였고 원판 확산법을 이용하여 methicillin 감수성을 측정하였다. Broth microdilution 법으로 vancomycin MIC를 측정하였다. 결과 : 총 27명에서 73회의 방문과 292회의 배양이 시행되었으며 총 67주의 S. aureus가 분리되었다. 이중 64주(95.5%)가 methicillin 내성이었다. 전비공 MRSA 보균율은 VRE를 보균하고 있었던 환자는 19명 중 11명(58%)에서, VRE를 보균하지 않았던 환자는 8명 중 3명(37.5%)으로 VRE 보균자에서 보균율이 더 높았다. 총 64주의 MRSA의 vancomycin MIC의 분포는 0.5-2㎍/mL였으며 2㎍/mL를 초과하는 균주는 발견되지 않았다. 64주 중 vancomycin MIC가 1㎍/mL인 균주가 54주(84.4%)로 가장 많았으며 2㎍/mL 6주(9.4%), 0.5㎍/mL 4주(6.3%)의 순이었다. 결론 : VRE 환자에서 S. aureus의 보균율은 비보균자 보다 높았으며 분리된 균주들은 대부분 MRSA였다. VRSA 균주는 발견되지 않았다. Background : The transfer of vancomycin resistance from vancomycin-resistant enterococci (VRE) to Staphylococcus aureus has been predicted. The purpose of this study is to determine the prevalence and antibiotics resistance of S. aureus among patients colonized with VRE. Methods : Between January 2001 and December 2001, a prospective study was performed at Pusan National University Hospital on 27 patients. Surveillance swabs from nasal cavity, axilla, perineum, and rectum were obtained at weekly intervals. Methicillin susceptability of S. aureus was determined by oxacillin disk diffusion test and minimum inhibitory concentration (MIC) for vancomycin by microdilution broth test. Results : Total of 292 swab cultures were performed and 67 S. aureus isolates were collected. 64 isolates (95.5%) were resistant to methicillin. The prevalence of nasal MRSA carrier in 19 patients colonized with VRE was higher than that in 8 patients not colonized with VRE (58% vs. 37.5%). In 64 MRSA isolates, MIC (㎍/mL) for vancomycin ranged from 0.5 to 2. No isolates with MIC >2 ㎍/mL were observed. MIC of 1 ㎍/mL was shown (observed) in 54 isolates, 2 ㎍/mL in 6 isolates, and 0.5 ㎍/mL in 4 isolates. Conclusion : The prevalence of S. aureus with colonization of VRE is higher than that without colonization of VRE. Most of S. aureus isolates were resistant to methicillin. VRSA isolates were not observed.