• 제목/요약/키워드: 박정길

검색결과 128건 처리시간 0.023초

진동피로에 의한 골판지 상자의 압축강도 저하율 (Decreasing Rate of Compression Strength for the Corrugated Fiberboard Container by Vibration Fatigue)

  • 김만수;정현모;박종민;박정길;김수일;박인식
    • 한국농업기계학회:학술대회논문집
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    • 한국농업기계학회 2003년도 하계 학술대회 논문집
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    • pp.347-352
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    • 2003
  • 농산물 포장화물의 경우 농산물의 손상은 겉포장 상자의 파손에 의한 압상이 주요 원인이다. 따라서 농산물 상자의 경우 압축강도를 특히 중요시 여기고 있으며, 한국산업규격을 비롯해 각종 농산물 관련 규정에서는 압축강도에 의한 상자의 품질관리를 규정화 하고 있다. 골판지 상자의 압축강도는 원단인 골판지의 구성 원지들(라이너, 골심지)의 품질과 이들의 구성 형태 및 상자의 외형 치수 비율에 따라 결정되므로, 원지의 링크라쉬(ring crush), 원단의 수직압축강도(edgewise compression strength)를 통해 상자의 압출강도를 관리하는 것이 보통이다. 또한 골판지 상자는 제작 후 유통 과정을 거치면서, 여러 요인에 의해 압축강도가 현격하게 저하되는데, 이중 수분 흡습에 의한 강도저하와 장기 누적하중, 진동 및 충격 등의 피로로 인한 강도 저하가 가장 크다. 여러 산업 분야에서 골판지 상자의 견고성 문제는 물품의 내수 및 수출시 제품에 대한 신뢰성 확보와 기업의 이미지 제고와 직결되는 중요한 사항이다. 특히, 세계 각 국의 농산물 시장이 개방됨에 따라 우리나라 농산물의 수출도 확대될 전망이고 또한 마땅한 대체재가 개발되지 않는 한 골판지 상자의 이용은 날로 증가될 것으로 전망된다. 따라서 골판지 상자의 압축강도와 내구성 향상에 대한 다각적인 연구가 절실하다. (중략)

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한.일간 지식정보의 생산과 흐름분석 - 문화분야를 중심으로 - (A Comparative Analysis on the Research Products of Each Other Between Korea and Japan - With an Emphasis on the Cultural Fields -)

  • 박정길;김용원
    • 한국도서관정보학회지
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    • 제33권2호
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    • pp.139-166
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    • 2002
  • 이 연구는 지난 1세기 동안(1900∼2000) 한·일 관계에 관한 지식정보의 생산과 흐름을 분석, 해석한 것이다. 특히 문화분야를 1)문화, 2)철학사상, 3)종교 4)예술, 5)어학, 6)문학으로 구분하여 한·일 양국이 상대국의 문화분야를 조사, 연구한 단행본의 종합목록을 작성하였다. 이것을 근거로 양국의 문화분야 연구물 생산 현황에 관한 통계자료를 작성하고 그 내용과 특성에 대해서 계량서지학적 분석과 질적 해석을 병행하였다. 연구의 결과 일본이 한국보다 문화분야의 단행본을 더 많이 생산하였다. 그러나 최관 15년간(1985년 이후 지금까지)에는 일본보다 한국이 문화분야 단행본을 106종 가량 더 많이 생산하였음이 밝혀졌다.

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저 사양 프로세서를 위한 실시간 주행 방향점 검출 기법 (A Real-time Detection Method for the Driving Direction Points of a Low Speed Processor)

  • 홍영기;박정길;이성민;박재병
    • 제어로봇시스템학회논문지
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    • 제20권9호
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    • pp.950-956
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    • 2014
  • In this paper, the real-time detection method of a DDP (Driving Direction Point) is proposed for an unmanned vehicle to safely follow the center of the road. Since the DDP is defined as a center point between two lanes, the lane is first detected using a web camera. For robust detection of the lane, the binary thresholding and the labeling methods are applied to the color camera image as image preprocessing. From the preprocessed image, the lane is detected, taking the intrinsic characteristics of the lane such as width into consideration. If both lanes are detected, the DDP can be directly obtained from the preprocessed image. However, if one lane is detected, the DDP is obtained from the inverse perspective image to guarantee reliability. To verify the proposed method, several experiments to detect the DDPs are carried out using a 4 wheeled vehicle ERP-42 with a web camera.

3차원 유한요소해석을 이용한 비우식성 치아의 수복 방법 (An Optimal Restoration Method of Noncarious Cervical Lesions Using Three-Dimensional Finite Element Analysis)

  • 우성관;김광훈;박정길;허복;손권
    • 한국정밀공학회지
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    • 제24권7호
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    • pp.112-119
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    • 2007
  • Cavities of Class V are caused by heavy occlusal loads due to bruxism and clenching habit. It is general to restore abfraction lesions with dental filler materials to reduce stress concentration. A material should be selected from various dental products based on long term clinical experiences or personal preference concerning filler methods. A quantitative criterion is necessary to make an evaluation of the results as dentists decide treatment methods and dental materials relying on their clinical experiences. The purpose of this study is to find an optimal restoration method and material for noncarious cervical lesions using the finite element method. An objective function was defined to minimize the sum of tensile and compressive stresses. Several models with different combinations of resins were suggested and compared in terms of the values of objective function. An optimal solution was to fill TetricFlow inside the lesion and Z100 in the remaining region with a thickness ratio of 0.125.

실내 이동로봇을 위한 거리 정보 기반 물체 인식 방법 (An Object Recognition Method Based on Depth Information for an Indoor Mobile Robot)

  • 박정길;박재병
    • 제어로봇시스템학회논문지
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    • 제21권10호
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    • pp.958-964
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    • 2015
  • In this paper, an object recognition method based on the depth information from the RGB-D camera, Xtion, is proposed for an indoor mobile robot. First, the RANdom SAmple Consensus (RANSAC) algorithm is applied to the point cloud obtained from the RGB-D camera to detect and remove the floor points. Next, the removed point cloud is classified by the k-means clustering method as each object's point cloud, and the normal vector of each point is obtained by using the k-d tree search. The obtained normal vectors are classified by the trained multi-layer perceptron as 18 classes and used as features for object recognition. To distinguish an object from another object, the similarity between them is measured by using Levenshtein distance. To verify the effectiveness and feasibility of the proposed object recognition method, the experiments are carried out with several similar boxes.

Lactobacillus helveticus와 Streptococcus thermophilus의 혼합배양에 관한 연구 -생육특성 및 배양조건- (Studies on the mixed culture of Lactobacillus helveticus and Streptococcus thermophilus in milk - Growth characteristics and cultural conditions for the mixed culture -)

  • 윤성식;박정길;유주현
    • 한국미생물·생명공학회지
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    • 제13권2호
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    • pp.151-156
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    • 1985
  • Lactobacillus helveticus YM-1 과 Streptococcus thermophilus CH-1을 환원탈지유 배지에 접종하여 생육특성 및 배양조건을 검토한 결과 두 균은 전형적인 공생을 나타냈으며 혼합배양시 최적 pH와 온도는 각각 6.5와 4$0^{\circ}C$였다. 또한 두 균 사이에는 단백질 분해력의 차이가 현저하였고 L.helveticus의 배양여액에는 S. thermophilus의 생육을 촉진시키는 물질이 함유되어 있음을 관찰하였다.

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지상강좌 1 - 비우식성 치경부병소와 치경부 복합레진수복의 응력분석 (Stress analysis of non carious cervical lesion and cervical composite resin restoration)

  • 박정길
    • 대한치과의사협회지
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    • 제48권4호
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    • pp.297-307
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    • 2010
  • Noncarious cervical lesions(NCCLs) are characterized as structural defects found on the tooth surface of the cement-enamel junction. Loss of tooth structure through noncarious mechanisms may vary in etiology and clinical presentation for each individual but presently many clinician now classify this as tooth failure of abfraction due to the stress applied in the cervical area of the tooth under oral physiological and pathological loads. In the current study, we investigated the stress distribution of maxillary premolar with NCCL using simulated 3D finite element analysis. The results were as follows: 1. In the sound maxillary premolar, the stresses were highly concentrated at cervical enamel surface of the mesiobuccal line angle, asymmetrically. 2. Once the lesion has been formed, the highest stress concentration was observed around the apex of the wedge shaped lesion. 3. In four types of NCCL, the patterns of stress distribution were similar and the peak stress was observed at mesial corner and also stresses concentrated at lesion apex. 4. Lesion cavity modification of rounding apex, reduced stress of lesion apex. 5. When restoring the notch-shaped lesion, material with high elastic modulus worked well at the lesion apex and material with low elastic modulus worked well at the cervical cavosurface margin.

과잉치와 유합된 상악 우측 제 1 대구치의 직접 치수 복조 및 2급 복합레진 수복 (Direct pulp capping and class II composite resin restoration of right maxillary first molar fused to supernumerary tooth)

  • 배인혜;최안나;손성애;박정길
    • 대한치과의사협회지
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    • 제56권6호
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    • pp.314-322
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    • 2018
  • Among developmental anomalies of tooth shape, fusion and gemination are comparatively common. Developed with different etiologies, both fusion and gemination show similar clinical features. Therefore, many clinicians have difficulty diagnosing those morpho-anatomic anomalies. The purpose of this study is to report malformed right maxillary first molar in a 20-year-old female. With the aid of computed tomography (CT), the tooth was diagnosed as fusion with supernumerary tooth and dental caries lesion was detected. After performing direct pulp capping, the tooth was permanently restored with microhybrid composite resin using direct method to alter union groove into smooth surface for improving oral hygiene management. Until 6 months of follow-up visits, patient's chief complaint was resolved and tooth is still vital. In conclusion, identifying exact anatomy, conservative treatment and improving oral hygiene are essential in managing unusual morphologic anomalies of tooth.

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고속도로변 사면경관의 인지적 관계분석 (Analysis on Perceptual Relationship in the Slope Scene of Highway)

  • 정성관;박정길
    • 한국조경학회지
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    • 제20권3호
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    • pp.33-43
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    • 1992
  • The perceptual characteristic on the slope scenery around highway is very similar as the general perceptual characteristic in the landscape. This process determines by the relationship between the scenery observers and the characteristics of its place. It is very important to have a analysis on highway slope scenery in our particular culture in Korea since our country's highways are done by cutting mountains : therefore, we have a lot of slopes around highways. The physical characteristics on the highway scenery determines how we should build scenery around highway to a satisfactory level. The results drawn from this research work are as follow: 1) The satisfaction for slope scene had been affected by sex, native and experience of travel. I thought that the slope scene having peculiar form will offer the highest satisfaction. 2) Psychological factor, reflected satisfaction of slope scene, 몽 a grip of three factors as the factor of evaluation, texture, formation, and presumption formula is : Satisfaction=1.04(Evauluation factor)+0.83(Texture factor)+0.15(Formation factor)+4.28)R2=0.69). 3) Vine among the vegetation componeents of slope scene highly correlated with the evaluation factor and grass, shrub correlated with the texture factor. 4) Rock among the structual components of slope scene highly correlated with the formation factor, and stockade, lattice correlated with the evalution factor. 5) Gradient among the properties which determined slope form, highly correlated with the formation factor.

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농산폐자원의 사요화에 관한 연구 제일보 밤송이의 전가수분해의 조건과 전가수분해액에 대한 효모생산 (Studies on the Feed Stuffs from the Agricultural Waste Part 1. Condition of pre-hydrolysis from chestnut-bur and yeast production from pre-hydrolyzate)

  • 유주현;양령;홍윤명;박정길
    • 한국미생물·생명공학회지
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    • 제3권3호
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    • pp.135-140
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    • 1975
  • 방송이를 4% H$_2$SO$_4$,용액으로 1.5kg/$ extrm{cm}^2$에서 30분간 전가수분해 시키면 원료에 대한 당화율은 21%을 얻었으며 생성된 당화액에 효모 Candida를 배양한 결과 당이용율은 20.5%에 불과하며 생성당에 대한 균체량의 비율은 21.25%을 얻을 수 있었다.

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