신경회로망을 이용한 이면비드 폭 예측에 관한 연구

정재원,김일수,박창언,김학형,서주환,김인주,심지연 한국공작기계학회 2008 한국공작기계학회 춘계학술대회논문집 Vol.2008 No.-

The development of robotic welding process is a very complex assignment because the system is affected by a number of process parameters which are very difficult to determine or predict in practice. The full automation welding has not yet been achieved partly because the mathematical model for the process parameters of a given welding task is not fully understood and quantified. Several mathematical models to control welding quality, Productivity, micro structure and weld properties in arc welding processed have been studied. However, it is not an easy task to apply them to the various practical situations because the relationship between the process parameters and the bead geometry is non-linear and also they are usually dependent on specific experimental result. Practically, it is difficult, but important to know how to establish a mathematical model that can predict the result of the actual welding process and how to select the optimum welding condition under a certain constraint. In this paper, an attempt has been made to develop an neural network model to predict the back-bead width as a function of key process parameters in the GMA (Gas Metal Arc) welding and to compare the developed models with the experimental results

축소형 하이브릿드 커플러에 의한 아날로그 이상기

周昌福,尹晶煥 慶南大學校 附設 工業技術硏究所 1997 硏究論文集 Vol.14 No.2

본 논문에서는 축소형 하이브릿드 결합기를 사용한 새로운 형태의 아날로그 이상기를 제시하였다. 전송선로의 등가화 회로해석의 결과 얻게된 축소 이론에 의해 기존의 ??전송선에 의해 구성되는 하이브릿드 결합기의 회로 레이아웃 면적을 80%로 줄일수 있다. 이러한 축소형 하이브릿드 결합기를 사용한 이상기의 동작특성은 기존의 하이브릿드 결합기를 사용한 이상기와 비교할때 작은 위상제어전압의 범위에서 선형 동작범위가 보다 크게 되며 광대역의 주파수 범위에서 보다적은 위상오차특성을 보인다. In this paper, a new type analog phase shifter using the reduced-size quadrature branch-line hybrid coupler is suggested and its operating characteristics are compared to the phase shifter using the existing ?? quadrature branch-line hybrid coupler. Using the reduced-size quadrature branch-line hybrid coupler, fabrication area can be reduced by 80% compare to the phase shifter using the existing ?? quadrature branch-line hybrid coupler. This suggested phase shifter showed linear phase shifting characteristics from 0°to 195°in the control voltage range of 0[v] ∼ -5[v], and its insertion loss is a little high but phase difference error is decreased much that of the phase shifter using the ?? quadrature branch-line hybrid coupler.

라텍스개질 콘크리트의 물-시멘트비에 따른 건조수축 특성

정원경,김성환,김동호,이주형,이봉학 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.A

Drying shrinkage cracking which may be caused by the relatively large specific suface is a matter of grave concern for latex modified concrete(LMC) overlay and rapid-setting cement latex modified concrete(RSLMC) overlay. LMC and RSLMC were studied for field applications very actively in terms of strength and durability in Korea. However, there were no considerations in drying shrinkage. Therefore, the purpose of this dissertation was to study the drying shrinkage properties of LMC and RSLMC with the main experimental variables such as cement types(ordinary portland cement, rapid setting cement), water-cement ratios and curing days at a same controlled environment of 60% of relative humidity and 20℃ of temperature. The drying shrinkage for specimens was measured with a digital dial gauge of Demec. The test results showed that the drying shrinkage of LMC and RSLMC were considerably lower with low water-cement ratio, respectively. This might be attributed to the interlocking of hydrated cement and aggregates by a film of latex particles, water retention due to hydrophobic, and colloidal properties of the latexes resulting in reduced water evaporation.

식장산의 식물상에 관한 연구

김주환,심정기,장인수 대전대학교 이과대학 기초과학연구소 1997 自然科學 Vol.- No.-

식장산은 해발 597.7m로서 북위 36°16′50″-36°19′30″, 동경 127°27′35″-127°30′00″에 위치하며, 행정구역상으로는 대전광역시 동구 세천동, 대성동과 낭월동에 위치한다. 식장산은 전형적인 온대중부에속하는 신갈나무와 졸참나무군락으로 대표되는 2차식생지역이지만, 출입통제와 같은 행정적인 이유로 인하여 그 보존상태가 매우 양호함에도 불구하고 현재까지 식물 목록의 작성조차 전무하였다. 유관속식물을 대상으로 1982년 4월부터 1997년 8월까지 채집조사한 결과, 소산식물은 3아문, 4강, 37목, 109과, 339속, 542종, 83변종, 13품종, 4잡종 등 총 643분류군으로 나타났다. 한국특산식물은 17과 18속, 17종, 3변종 등 총 20종류로 소산식물의 2.7%이며, 희귀 및 멸종위기식물은 관중, 개족도리, 보춘화 등 3과 3속 3종류이었고, 유용식물은 식용식물 257종류, 약용식물 194종류로 나타났다. 또한, 귀화식물은 14과, 25속, 29종, 1변종 등 총 30종류로 우리나라 전체 귀화식물종 182종류의 16.3%이며, 소삭식물의 4.6%로 나타났다. Mt. Shikjang is located at 36" 16' 50"- 36" 19' 30" in latitude, at 127。27' 35"- 127" 30'00" in longitude, and on the Sechon-dong, Taesong-dong and Nangwol-dong, Tong-ku in Taejon Metropolitan City. Mt Shikjang shows the typical vegetation patterns including the middle area of temperate region represented by the secondary forests of Quercus mngolicu and Q. serrata. Owing to the public p개tection on the origin of running water and huge antena on the top, the condition of condition seems very good But there' s no report on the flora or plant list of Mt Shikjang yet The results of plant collection and their investigatmn from April in 1989 to August in 1997 are as follows : The vascular plants consist of total 643 taxa, 4 hybnds, 13 래금, 83 varieties, 542 species, 339 genem, 109 families, 37 orders, 4 classes, 3 subphyla In this area the Korean endemic plants are 20 taxa(2.7% among total 643 taxa) : 3 varieties, 17 species, 18 genera, 17 families. And rare and endangd plants are 3 taxa : Dryopteris crassihizoma, Asarum maculahun, Cymbidwn goeringii. Among the useful plants, there are 257 kinds of edible plants and 1% kinds of medicinal plants. Also, the nzlhnalized plants are 30 taxa(4.6% among total 643 taxa and 16.3% among the total naturalized plants in Korea) : 1 variety, 29 species, 25 genera, 14 families.

전력계통의 부하주파수제어를 위한 신경망 PID제어기 설계

정형환,김상효,이정필,주석민 東亞大學校 大學院 1998 大學院論文集 Vol.23 No.-

This paper has presented a method for self-tuning the PID controller suing a BP method of multilayered NNs. The proposed controller employ input signal as a learning signal of PID control. The proposed controller is applied to load-frequency control of power system and it is investigated a dynamic characteristic. The simulation results shows that proposed NN STPID controller has the good dynamics responses against load disturbances.

매복된 하악 제3 대구치 발치시 항생제 투여의 효용성

여환호,박주철,정종훈,강태호 大韓顎顔面成形再建外科學會 1999 Maxillofacial Plastic Reconstructive Surgery Vol.21 No.4

To evaluate the efficacy of antibiotic administration in the impacted mandibular third molar extraction the author investigated 107 patients requiring extraction of the lower third molar who visited at the Department of oral and maxillofacial Surgery. Chosun Dental Hospital and were healthy without medical problems and had no signs and symptoms of infection around the lower third molar. The patients were divided into 4 groups according to the method of antibiotics administration : 13 patients without antibiotics administration(group 1), 30 patients with only intravenous injection of Cefazoline 2.0g 30 minutes before the procedure(group 2), 39 patients with intravenous injection of Cefazoline 2.0g 30 minutes before the procedure and oral administration of follow-up dosages of Augmentin for 1 day(group 3), and 25 aptients with intravenous injection of Cefazoline 2.0g 30 minutes before the procedure and oral administration of follow-up disages of Augmentin for 3 day(group 4). Infection rates after extraction wer calculated and compared according to gender, the age of the patients, the level of impaction, and also compared between four groups. The results were as follows. 1. The overall infection rate was 8.4%. 2. The infection rate was higher in male(11.9%) than in female(4.2%), but there were statistically no significant differences between them. 3. Infection rate was lower in patients under age 30(7.2%) than in patients over age 30(12.5%), but there were statistically no significant between them. 4. Infection rate was higher in patients with complete bony impacted tooth(11.1%) than in patients with partial bony impacted tooth(6.5%), but there were statistically no significant differences between them. 5. Infection rate was 7.7% in group 1, 10.0% in group 2, 10.3% in group 3, 4.0% ingroup 4 and there were statistically no significant differences between groups. In summary, it is more important to extract the impacted lower third molar under aseptic condition and to minimize the injury of tissue if possible than to administer the preventive antibiotics in reducing the infection rate in healthy patients without medical problems who had no signs and symptoms of infection around the lower third molar.

양극성 반고관절 성형술을 이용한 대퇴 경부 골절의 치료

오정환,조병주,안의환 건국대학교 의과학연구소 1998 건국의과학학술지 Vol.8 No.-

Problems of nonunion, avascular necrosis of the femoral head, and loss of fixation are frequently encountered in the management of femoral neck fractures and high complication rates after closed or open reduction and internal fixation technique were reported due to poor bone quality or lack of cooperation in elderly patients. So, another option of hemiarthroplasty for the management of the femoral neck fractures were recommended, especially in elderly patients. We reviewed 20 bipolar hemiarthroplasties which had been performed from April, 1990 to March, 1996 for the femoral neck fractures and followed up for a minimum of 1 year and are reporting their results.

셀레콕시브 및 그 합성유도체들의 항암활성 스크리닝

박정란,강진형,구효정,노지영,류형철,박상욱,고동현,조일환,이주영,황다니엘,김인경 한국약제학회 2003 Journal of Pharmaceutical Investigation Vol.33 No.2

Selective COX (cyclooxygenase)-2 inhibitors including celecoxib have been shown to induce apoptosis and cell cycle changes in various tumor cells. New inhibitors are recently being developed as chemomodulating agents. We evaluated celecoxib and screened 150 synthetic compounds for anti-proliferative activities in vitro. Effects of celecoxib on COX activity, cell growth, cell cycle distribution, and apoptosis induction were determined in A549 COX-2 overexpressing human non-small cell lung cancer (NSCLC) cells. The COX inhibition of celecoxib increased with concentration up to 82% at 1μM after 24 hr exposure. Forty μM and 50μM of celecoxib induce G_1 arrest, and TUNEL-positive apoptotic cells, respectively. Among 150 compounds, several compounds were selected for having greater COX-2 inhibitory activity and higher selectivity than celecoxib with growth inhibitory activity. Celecoxib showed concentration-dependent COX inhibitory activity, and ability to induce cell cycle arrest and apoptosis in human NSCLC cells in vitro. Among synthetic analogues screened, several compounds showed promising in vitro activity as COX-2 inhibitory anticancer agents, which warrant further evaluation in vitro and in vivo.

FEM을 이용한 선삭가공 절삭조건의 영향 분석

임세환,송춘삼,홍석관,강정진,김주현 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-

A plane strain finite element model is developed to simulate turning with continuous chip formation using adaptive remeshing during the thermal-mechanical coupled analysis. Comparisons between the experimental and simulation results for cutting forces are performed to validate FE analysis results. Influences of machining parameters such as depth of cut, cutting speed and feed rate on cuting force and shear angle are analyzed by Taguchi method. The more depth of cut and feed rate result in the increase of cutting forces, but the rates of increase are decrease due to the larger shear angle. As the cutting speed increases, von Mises stress of workpiece near the tool tip decreases because the strength of specimen decreases at high temperature above 500℃. This thermal effect on cutting force is negligible because the affected area is very localized and the average values of von Mises stress in the shear plane are the same among the diverse cutting parameters.

질소산화물의 급성 노출로 인한 폐 손상 1례

김정호,김대환,손병철,이창희,김정원,문덕환,이채언,김주인 대한산업의학회 2000 대한직업환경의학회지 Vol.12 No.2

Objectives : Lung injuries due to exposure to nitrogen oxides can occur in various process in industry. We experienced a case of chemical pneumonitis induced by accidental inhalation of nitrogen oxides emitted from the bath in an acid dipping operation. Case : Dyspnea, cough and blood-tinged sputum production, cyanosis, and tachypnea occurred after exposure to oxides of nitrogen. There were bilateral diffuse ground glass opacities in simple chest radiography and high resolutional computed tomography, hypoxemia in arterial blood gas analysis, mixed ventilation defect and reduced diffusion capacity in spirometry. As an oxygen and supportive therapy, after hospitalization, was given, the patient recovered completely from the lung injury on the 8th day after admission. There was no evidence of delayed onset of bronchiolitis obliterance or pulmonary edema in a follow-up for about 6 months. Conclusions : Acid dip operation require more efficient hooding and exhausting system for the prevention of lung injuries caused by inhalation of nitrogen oxides. Also health education for worker need.