고주파수 PWM 제어를 이용한 ABS의 특성 평가에 관한 연구

김병우,이용주,박호 한국공작기계학회 2004 한국생산제조학회지 Vol.13 No.2

In general the surge pressure generated in hydraulic systems causes noise, vibration and odd effect to the system. To reduce the surge pressure, high frequency PWM control of 20KHz was attempted. To estimate the braking noise caused by surge, a vehicle equipped with on-board ABS hydraulic modulator has been experimented with respect to the various breaking condition. Though this experiments, it was found that breaking noise has been reduced using high frequency PWM control method compare with low frequency method. To evaluate high frequency control in practice, including verification of general functionality, EM tests was experimented. Its was found that it is necessary to have the solution to electromagnetic interference(EMI) generated by switching elements.

生體實驗用 900 MHz 電磁波의 인가장치 설계연구

김윤명,권용일,문병기,성주영 단국대학교 1999 論文集 Vol.34 No.-

In this paper, we made the space 900 ㎒ electromagnetic field, using the strip line which has been applied to EMC test for communication equipments and vehicles etc.. We analyzed electromagnetic distribution and scattering parameters of strip line to obtain the characteristic of this designed strip line, using the numerical method of FDTD(Finite Difference Time Domain).

短期所得林産物 市場接近物量의 輸入管理制度 改善方案

金義慶,鄭秉憲,李聖淵,朱麟源 한국산림경제학회 2002 산림경제연구 Vol.10 No.2

본 연구는 밤, 잣, 대추에 대하여 이루어지고 있는 최소시장접근물량에 대한 수입관리제도의 문제점을 살펴보고 그 개선방안을 도출하는데 목적이 있다. 주요 결과를 보면 밤의 경우 1995년 이후 평균 10%정도의 낮은 수입이행률을 보이고 있으며, 잣의 경우 환율 급변에 의한 환차손으로 수입관리기관이 손해를 보거나 시장조절기능도 미약하다는 문제점을 가지고 있는 것으로 나타났다. 따라서, 수입관리방식은 잣의 경우 현재의 국영무역에서 수입권공매방식으로, 밤의 경우 현재의 수입권공매방식을 선착순배정방식이나 수입허가제방식으로 바꾸는 것이 바람직한 것으로 분석되었다. 또한, 수입시기를 국내산 성출하시기를 피하여 수입하는 것이 바람직하며, 수입냉동품, 세관검사 및 저가신고에 대한 적절한 수입관리대책도 필요한 것으로 나타났다. The objectives of this study are to analyze the problems of import administration system for minimum market access of chestnut, Korean pine nut and jujube, and suggest its improvement measures. Major findings are as follows : The fill rate of minimum market access for chestnut was very low of about 10% since 1995. The import administration agency of Korean pine nut suffered the loss from abrupt exchange rate change and had weak market control, Therefore it was suggested that Quota Auction System is better than current State Trading System for Korean pine nut, and First-Come First-Served System or Import License System is better than current Quota Auction System for chestnut. And it is desirable to import during the period beyond the main harvesting season for domestic products, and needed to construct the adequate aministration measures for forzed product import, customs examination and low price declaration.

철근콘크리트 휨부재의 피로특성에 관한 실험적 연구

김영진,노병철,장세창,변근주 연세대학교 산업기술연구소 1991 논문집 Vol.23 No.2

In recent years, considerable interest has developed in the fatigue strength of reinforced concrete members subjected to cyclic loading for the wide-spread adoption of ultimate strength design procedures, the higher strength materials and the new recognition of the effect of repeated loading on structures such as bridges, concrete pavements and offshore structures. In this study, a series of experiments is carried out to investigate the fatigue characteristics of deformed bars and underreinforced simply supported beams, The 69 reinforcing bar specimens with grade SD30 and designation of D16, D22, D25, and 24 beam specimens with D16 bars are prepared for this study. From these series of tests, it is found that ⅰ) the decrease of the bar diameter results in increased fatigue life, ⅱ) the fatigue life of the bars embedded as main reinforcement within a concrete is longer than that of bars in the air. ⅲ) the fatigue strength of beams at ?? cycles with steel ratio of 0.61% and 1.22% is 64.5% and 63.2% of the yielding strength, respectively. It is concluded that the low steel ratio has no significant effect on fatigue strength of underreinforced beams and the fatigue life underreinforced concrete beams can be predicted conservatively by the fatigue life of reinforcing bar.

신이식후 거부반응으로 적출된 이식신 혈관벽의 Dendritic cell에 대한 면역조직화학적 연구

김병주,박호철,고석환,주흥재 大韓移植學會 1993 Korean Journal of Transplantation Vol.7 No.1

치아종에 대한 증례보고

백병주,김재곤,주훈,양정숙 大韓小兒齒科學會 1995 大韓小兒齒科學會誌 Vol.22 No.2

Odontomas are most common benign odontogenic tumors, and have been defined as "mixed odontogenic tumor composed of epithelial and mesenchymal cells". Many authors are considered to be malformations rather than neoplasm. The etiology of odontoma is uncertain but hypothesized to involve local trauma, infection, inheritance or mutant gene interference with genetic control of tooth development. The recent classification by WHO divides odontoma into 2 groups such as complex odontoma and compound odontoma. Odontomas are usually asymptomatic and are usually discovered on routin dental radiographs. The most frequently encountered symptoms are impacted tooth and swelling. Radiographically, it appears as an irregular mass of calcified material surrounded by a radiolucent band. The possibility of an ameloblastic odontoma must be kept in mind during the differential diagnosis. Surgical excision and histopathological examination of the lesions is recommended. Following removal of the odontoma closing the incision and allowing the tooth to erupt spontaneously was considered. Hitchin suggested that spontaneous eruption may not occur if the root of the impacted tooth is completed. Failure to erupt would require a 2nd surgical exposure to place an orthodontic attachment. This report presents the result in treating patients, whose chief complaint was delayed eruption of teeth due to odontoma.

傳門大學 海洋土木科 敎育課情 開發硏究

林秉龍,鄭營采,申文燮,李東周,張仁奎,金榮燮 군산대학교 1982 群山水産專門大學 硏究報告 Vol.16 No.1

To carry out the study on the curriculum development for the ocean civil department in junior college, we collected and analyzed data which are on the curriculum development or improvement of the inside and outside of the country. We also gathered the opinion through the inquiring paper investigation and the consultation to the industrial organization, concerned school and authorities during 6 months from May, 1981. In addition, we analyzed and compared the present curriculum of special civil and ocean civil department in junior college. On the basis of above methods, a result we made a model curriculum shown in Table 10. Under current trend and circumstances of the industrial society, the best way for the curriculum development is to make like the course curriculum. But, it is is difficult to make the course curriculums of the ocean cavil department at present. Because the ocean civil is a branch of general civil engineering, furthermore the oceanic industry of our country is not developed well. So, dividing the major subjects in four fields for operating the model curriculum flexibly with the characteristics of the community and college, we developed the suitable curriculum in junior college course, such as general basic field, special basic field related to the ocean, special basic field related to the general civil and application field. We also tried to entensify the subjects of general basic field, special basic field related to the ocean, and to simplify the number of subjects in the model curriculum. Of course we can't say this model curriculum is perfect. But we believe firmly that the results of this paper will be a help to another curriculum development or improvement study for the ocean civil department in junior college.

고주파수 PWM제어를 이용한 ABS의 맥동 저감에 관한 연구

이용주,김병우,박호 한국공작기계학회 2003 한국생산제조학회지 Vol.12 No.3

The solenoid valve in ABS hydraulic modulator is a two directional on-off valve and is controlled by around 100㎐ high speed pulse width modulation. When the valve is switched from open state to closed state, noise and vibration due to pressure surge phenomena in the hydraulic line and wheel cylinder are made. In this study, we identify pressure surge phenomenon in the braking process of a ABS, and investigate the way to reduce the phenomenon. For the purpose of theoretical analysis on the pressure surge in the closed state hydraulic line, characteristic curve method based on wave equation was utilized. To reduce the surge, high frequency control of 20KHz was attempted. The result showed that the surge pressure of 50% was reduced compared to one observed in the low frequency control. Duty variation of high frequency can control current of solenoid valve and prevent sudden changed of displacement.

專門大學海洋土木科模型敎育課程 修正開發硏究

李東周,林秉龍,張仁奎,申文燮,金榮燮,朴昌圭,金康洙 군산대학교 1988 群山水産專門大學 硏究報告 Vol.22 No.1

This is a study to modify the curriculum of the ocean civil engineering department in junior college. We collected and analyzed data which are concerned on the curriculum development or improvement, the marine techniques and the ocean policy. And then we also gathered the opinions of the professors serving at the ocean civil engineering department by holding several conferences and investigated the opinions of the ocean civil engineers serving at the industrial organization by way of the inquring papers. In addition we collected the advices of educational specialists and ocean civil specialists by visiting personally. On the basis of above opinions we developed the jobs of graduates and made a model curriculum shown in Table 6. We tried to intensify the subjects of special basic field related to the ocean & civil engineering and the subjects of basic experiment & practise. The ocean observation practise was newly formed and the E. D. P.S was reinforced.

발전소 디지털 제어계통의 신뢰도 평가기술에 대한 고찰

문채주,김홍렬,조병수 木浦大學校 工業技術硏究所 1999 工業技術硏究誌 Vol.9 No.-

As applications of digital system are increasing in nuclear power industry, there are increasing on importance of their reliability assessment. This paper describes definition, analysis methods and procedure of reliability for digital system in terms of hardware. The reliability analysis is classified as qualitative method and quantitative method. This paper presents a representative qualitative method, FMEA, and three quantitative methods, Reliability Block Diagram, Fault Event Trees, Markov state Transition Method, which can be applicable in power plant. The comparisons of three quantitative methods are presented for analyst to select a suitable method according to environments of applications. The procedure is also presented for systematic safety and reliability analysis of digital system. Each step of the procedure is described in terms of objective, necessity, method and consideration.