DTFC에 의한 對稱形 패� 스위칭 컴퓨터망의 POWER特性

박형식,양회국 경북대학교 공과대학 1981 工大硏究誌 Vol.10 No.-

The Performance of DTFC(Drop and Throttle Flow Control), a kind of IBL(Input Buffer Limit) scheme, is observed with respect to several values of threshold L, which controls to accept input packets and transit packets into the input buffer of a node, in the symmetrical packet-switched network. Performance measures are throughput, delay, and power of a tradeoff between throughput and delay. Computer results show that there exist a suboptimal threshold L with respect to throughput, but not with respect to power.

알루미나 세라믹스의 분위기 압력변화에 따른 마모특성에 관한 연구

박홍식,김용완,김형자,김영대 釜慶大學校 1996 釜慶大學校 論文集 Vol.1 No.2

This study was investigated to the tribology characteristics for the alumina ceramics(Al₂O₃) in the variation of ambient pressure. The sliding wear test was carried out under the condition of the various applied load, sliding distance and the ambient pressure with mate specimen made of STB2 stee. The results obtained are as follows : 1. As the ambient pressure decreases, the friction coefficient increases, becasue the protective layer made of absorption substance can not be fromed due to decrease of the amount of ambient gas. 2. The friction coefficient of purity 85% alumina is higher than that of purity 95% and 99.7% alumina because of the influence of heat accumulation. 3. As the applied load increases in each ambient pressure, the friction coefficient increases due to brittle fraction of alumina grain and great action of cohesion. However, the gap of the friction coefficient by the variation of the contact load is small in the vacuum. 4. The friction coefficient regarding the variation of sliding distance increases by on inital 60 meters of the sliding distance, however, the friction coefficient is almost constant after the sliding distance.

石炭, 洋灰關聯産業이 嶺東地域經濟에 미치는 波及效果 分析

박형래,강영갑,양정식,류한천 강릉대학교동해안지역연구소 1994 東海岸硏究 Vol.5 No.1

본 논문의 목적은 지역산업연관표를 이용하여 영동지역의 산업연관 관계를 계량적으로 분석하는데 있다. 이러한 산업연관 분석방법은 영동지역의 산업상호간 경제활동과 구조적 특징을 체계적으로 분석하고 장래의 산업 변화에 대한 예측을 가능하게 한다. 본연구의 결과에 나타난 몇가지 중요한 점은 다음과 같다. 첫째, 석탄, 양회산업은 지역산업연관효과가 매우 높은 수준으로 측정됨으로써 이들 특화산업이 지역발전의 선도산업으로서 중요한 역할을 수행하고 있음을 보여주고 있다. 둘째, 이들 두 산업이 영동지역내에서는 중요한 산업이지만 양회산업의 경우 지역전체 생산에서 차지하는 비중이 매우 높은 산업임에도 불구하고 고용승수로 측정되는 고용효과 측면에서는 그 영향이 그리 크지 않은 것으로 나타났다. 이것은 시멘트 산업이 자본집약적인 장치산업으로서 자본의 규모에 비해 고용자를 많이 사용하지 않기 때문인 것으로 평가된다. The purpose of this study is to analyze the quantitative characteristics of the Young-Dong regional economy in industrial interleatedness by using the 1990 I-O table. The analysis of this structural character and industrial interrelatedness makes it possible to estimate the current structural problems and future prospects of Young-Dong regional economy. The findings of this study can be summarized as follows: 1)The coal mining and cement industries sector have relatively high and wide-spreading positive impacts on the regional output and income. 2)Above two sectors showed different impacts pattern on the employment. Coal mining sector gives relatively higher impacts on the regional employment but cement industry sector gives lower impacts on the regional economy because cement industries sector is labor saving industries with large equipment requirement.

前腕部 經穴 取穴에서 骨度分寸法과 一夫法의 比較 硏究

박히준,채윤병,차웅석,박종배,이혜정,이향숙,인창식,고형균,김수영,최일환,김강식,문정배,배기태,유경환,육근영,정병주,손인철,임사비나 WHO COLLABORATING CENTRE FOR TRADITIONAL MEDICINE 2004 東西醫學硏究所 論文集 Vol.2004 No.-

Background : The cun measurement System, an essential and convenient method in locating acupoints, has been widely used in the practice of acupuncture. However, traditional cun measurement has been criticized for its lack of reliability. Objectives : The purposes of this study are to determine if one cun measured by the directional methods have a consistency with that of proportional methods and to investigate which factors are related with these differences, especially in forearm. Methods : The distance between the elbow crease and the wrist crease of forearm was compared to a reference value of one cun obtained by the directional method. In this method, one cun is one third of the distance between index finger and Small finger of a subject, measured at proximal interphalangeal joint. In addition, to investigate the factors influencing the differences between these two methods, we measured the height and body weight and calculated body mass index (BMI). Finally we analyzed the factors correlated with these lengths by linear regression test. Results : The results showed that one cun obtained by the directional methods were significantly different from one cun by the proportional methods in forearm. It was demonstrated that the length acquired with the directional method was more correlated with body weight and body mass index, while the length obtained by the proportional method was more correlated with the height.

전기유동유체의 전기적 내구성에 대한 실험적 고찰

박우철,이현창,이형식 三陟大學校 2001 論文集 Vol.34 No.1

This paper presents experimental results on material properties of an electro-rheological(ER) fluids subjected to electrical fatigues. As a first step, two types of ER fluids made of arabic gum and methy1 cellulose(MC) choosing 25% of particle weight-concentration. Following the construction of test mechanism for electrical durability of ER fluid, the dynamic yield shear stress and current density of the ER fluids are experimentally distilled as a function of electric field. The yield shear stress of operated ER fluids are distilled and compared with those of unused ER fluids. In addition, the surface roughness of the employed electrode are evaluated as a function of the number of the electric-field cycle.

熱間 알미늄 押出型材의 型材係數에 관한 연구

박정수,이형식 연세대학교 산업기술연구소 1975 논문집 Vol.6 No.1

In the hot extrusion of aluminum alloys for architectural uses, a wide variety of extrusion shapes are encountered under various requirements necessitating it different operational conditions to adopt. However, the prevailing cost estimate for the extrusion shapes practised so far among the extruders in this country has been a unique cost per kilogram without regard to the geometric configuration and its operational condition, which has presented itself as one of the most unreasonable aspect in the plant operation and for the estimation of their prices. In this study, a shape factor that indicates the degree of relative complexity in the extrusion process for every extrusion shape reflecting its geometric configuration and operational condition was established, and the relationship between the shape factor and the productivity was observed through the practical operation. It was found that a logarithmic relationship was existing between the shape factor and the extrusion output per hour, where the output being decreased with the increase of the shape factor. And also, empirical equations were established for obtaining the extrusion output per hour with the variable of the shape factor. Meanwhile, the extrusion recovery, the life span of die and the fuel and power consumption in the extrusion were analyzed, which, together with the extrusion time, were used in establishing a formula for an overall cost estimate for every extrusion shape. There were marked differences in the overall costs of aluminum shapes, and the costs were dependent on the shape factor, type of die and the applicable dimensional tolerances. Among them, the shape factor was found to be the most dominant agent in the cost estimate. Comparing with the conventional method of unique cost estimation, the formulas for calculation of the overall costs for every shape which were newly established in this study provide the most reasonable basis for the pricing of extruded aluminum shapes, thereby making it possible to benefit both the manufacturers and the consumers.

Mirizzi 증후군의 변형된 분류와 치료

김형철,강길호,채만규,김성용,백무준,이문수,박상흠,이문호,김창호,송옥평,조무식,박희주 순천향의학연구소;Soonchunhyang Medical Research Institute 2000 Journal of Soonchunhyang Medical Science Vol.6 No.1

Purpose : The Mirizzi syndrome is relatively rare and preoperative diagnosis of this disease is difficult. In 1978, Morelli suggested the subclassification of the Mirizzi syndrome into acute or chronic form. We experienced 5 cases of acute form. We analysed clinical features, preoperative radiologic findings and operative findings of 18 cases including acute forms which were diagnosed as Mirizzi syndrome and should suggest the modified classification of Mirizzi syndrome for choice of appropriate treatment. Method : From January 1995 to December 1998, 18 cases, of which 8 cases were diagnosed at Soonchunhyang University Chunan Hospital, and 10 cases were reported in the Korean Journal were retrospectively analysed with regard to clinical features, preoperative radiologic findings and operative findings. According to the clinical features, whole cases were divided into type Ⅰ(acute form) and type Ⅱ(chronic form) and then each type of cases were subclassified according to preoperative radiologic findings and operative findings. Results : Of 18 cases there were 5 cases in type Ⅰ(27.8%), 13 cases in type Ⅱ(72.2%). Type Ⅱb was most common. Type Ⅰa cases were treated only with cholecystectomy. We applied cholecystectomy, T-tube choledochostomy and patch technique in type Ⅰb and thpe Ⅰc cases. Cholectystectomies including removal of gallstones and internal drainage procedures were done in type Ⅱ chronic forms. Conclusion : The acute form(Type Ⅰ) of Mirizzi syndrome was suggested by Morelli might be subclassified into typeⅠa,Ⅰb and Ⅰc following the presence of the necrotic defect in common hepatic duct. Through the modified classification of Mirizzi syndrome based on clinical feature, preoperative radiologic findings and operative findings, we can choice appropriate treatment.

머리염색이 인체에 미치는 영향

윤형식,황성호,이현륭,김수호,박연석,권낙현,정호진,김동훈,노현주,홍성호,박병찬,이관,정해관 東國大學校醫學硏究所 2002 東國醫學 Vol.9 No.1

일상생활에서 모발염색은 흔히 접할 수 있는 미용의 한 종류로 특히 젊은층을 중심으로 폭발적으로 유행하고 있다. 염색을 위항 사용하는 약제는 표백제와 발색제 등 각종 화학약품이 사용되고 있으나 이로 인한 건강장해에 대한 연구는 그리 많지 않다. 저자들은 염색이 인체의 모발건강에 미치는 영향을 파악하기 위하여 염색과 관련된 주관적 증상과 모발의 변화에 대한 실험적 연구를 시행하였다. 동국대학교 경주 캠퍼스 재학생 80명을 대상으로 설문조사를 시행하여 염색 유 ·무 및 염색 후에 경험한 증상에 대해 설문 조사하였고, 의과대학 재학생 46명을 대상으로 피부 반응 테스트를 실시하였다. 또한 염색 전후의 모발 탄성도를 측정하였고 모발의 상태를 파악하기 위해 전자 현미경검사를 실시하였다. 설문조사 결과 염색 전에 비하여 염색 후 안구혼탁, 안구건조, 시력저하, 발진 및 접촉성 피부염, 모발손상, 모근손상 등의 증상을 더 많이 경험한다고 호소하였다(p<0.05). 모발손상과 모근손상은 헤어드라이어 사용 빈도에 따라 증가하는 것으로 조사되었다(p<0.05). 피부반응검사에서 가려움증이 가장 많은 증상이었으며 이는 여성보다는 남성에서 높은 것으로 조사되었다. 염색 전후의 모발장력은 염색 전 134.5±10.37g, 염색 128.0±30.69g, 염색 이틀 후 112.5±19.69g으로 나타났다. 염색 전후의 모발의 전자현미경 케라틴 층이 현저히 감소하고 모발이 가늘어지는 차이를 보였다. 염색은 모발손상, 모발 케라틴 손상 및 모근 손상, 발진 및 접촉성 피부반응, 안구혼탁, 안구건조, 시력 저하를 유발한다. 따라서 염색약으로 인한 손상에 대한 주의와 예방이 필요하다고 생각한다. 예방대책으로 염색 전 피부테스트를 통한 적합성 여부를 판단하는 것이 필요하며 가급적 염색을 피하는 것이 좋을 것이다. 염색약에 발암물질이 포함되어있다는 보고도 있어 염색 제조사의 철저한 실험과 염색 물질의 선별이 염색으로 인한 부작용을 최소화하는데 중요한 역할을 할 것이다. Hair coloring has became one of the most popular cosmetic activities to younger generations during last decade. However, there are few studies on the health effect of widespread use of chemical dyes. This study was conducted to study the effects of hair coloring dye on hair and other systems. We conducted a questionnaire survey of 80 persons in Kyongju campus, Dongguk University. We have done open patch skin test on 46 medical students. We also conducted scanning electron microscopy to examine the hair strength and structure before and after hair coloring process. Injury of hair and hair bulb, contact dermatitis, turbid eyes, xerophthalmia, and poor visual acuity were the main symptoms complained after hair coloring (p<0.05). Injury of hair and hair bulb were increased by frequency of hair-dryer use(p<0.05). In open patch test, pruritus was complanined by more than half of the subjects. Mean strength of hairs before and after hair coloring was as follows; 134.5 (SD 10.37)g before hair coloring, 128.0 (SD 30.69)g immediately after hair coloring, and 112.5 (SD 19.69)g after two days. The scanning electron microscopic findings of hair surface before and after hair coloring showed decreased keratin layer and thinning of the hair. Hair coloring induces injury to hair, its keratin layer, and hair bulb as well as contact dermatitis, turbid eyes, xerophthalmia, and poor visual acuity. Therefore, we think that precaution is needed in use of hair coloring dye. To prevent complications induced by hair coloring dye, it is necessary, especially to those with allergy or skin disorders, to perform skin test before action and avoid hair coloring whenever possible. Longterm health effects of hairdye should be studied and manufacturing companies should try to minimize complications induced by hair coloring dye.

非線形 理論에 依한 채터 解析

이형식,정준기,박태형 연세대학교 산업기술연구소 1983 논문집 Vol.15 No.2

The chatter analysis has been studied by many authors using non-linear. In this study, the stability chart obtained from experimental work with a lathe was qualitatively compared with the result of chatter analysis by non-linear theory. Experimental results verify that the stability of the machining process is affected by the width of cut in the following manner. As the chip width is increased from zero with the rotational speed of the workpiece kept constant, three ranges are distinguished; (a) unconditionally stable range, (b) conditionally stable range, (c) unstable range. In the conditionally stable range the system is stable for small disturbances but unstable when these exceed a certain level. When the chatter occurs, the amplitude initially increases and stabilizes itself at a finite level. This phenomenon agrees well with the analysis of non-linear theory qualitatively.

입상활성탄에 의한 방향족, 지방족고리 아민류 및 아미노산의 액상흡착

이성식,김형준,유명호,박성은 동아대학교 공과대학부설 생산기술연구소 1998 生産技術硏究所硏究論文集 Vol.3 No.1

Equilibrium studies for the adsorption of aromatic, alipatic cyclic amines and amino acid from aqueous solutions onto granular activated carbon have been carried out at 298K. Two and Three-parameter isotherms were tested. Among the equations tried, the two-parameter equations of Freundlich equation yield a better fit, The Langmuir equation, However gives the poorest overall fit. For three-parameter isotherm equation, the Redlich-Peterson equation gives the most satisfactory fit over the entire range of concentrations. The adsorption amounts of the aromatic amines onto GAC increase with the number of methyl group in pyridine ring.