Effect of corrosion on the ultimate strength of double hull oil tankers – Part II: hull girders

김도균,박대겸,Dong Hee Park,Han Byul Kim,김봉주,서정관,백점기 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.42 No.4

Numerous oil tanker losses have been reported and one of the possible causes of such casualties is caused by the structural failure of aging ship hulls in rough weather. In aging ships, corrosion and fatigue cracks are the two most important factors affecting structural safety and integrity. This research is about effect on hull girder ultimate strength behavior of double hull oil tanker according to corrosion after Part I: stiffened panel. Based on corrosion data of Part I (time-dependent corrosion wastage model and CSR corrosion model), when progressing corrosion of fourtypes of double hull oil tankers (VLCC, Suezmax, Aframax, and Panamax), the ultimate strength behavior of hull girder is compared and analyzed. In case of the ultimate strength behavior of hull girder, when occurring corrosion, the result under vertical and horizontal bending moment is analyzed. The effect of time-dependent corrosion wastage on the ultimate hull girder strength as well as the area, section modulus, and moment of inertia are also studied. The result of this research will be useful data to evaluate ultimate hull girder strength of corroded double hull oil tanker.

구연산과 섬유소의 치근면 도포가 성견 치주조직 재생에 미치는 영향

김도균,박재완,이재목,서조영,Kim, Doe-Gyeun,Park, Jae-Wan,Lee, Jae-Mok,Suh, Jo-Young 대한치주과학회 1994 Journal of Periodontal & Implant Science Vol.24 No.1

성견 견치의 인위적 골결손부에 치근활택술 시행 후, 섬유소 처리, 구연산 탈회, 섬유소 처리및 구연산 탈회가 치주조직 재생에 미치는 영향을 관찰하기 위하여 치근장축 방향으로 절편을 1일, 3일, 7일, 14일, 21일 간격으로 제작하여 광학현미경으로 관찰한 결과 다음과 같은 결론을 얻었다. 술후 1일째 대조군을 제외한 섬유소 단독도포군, 구연산 단독도포군 및 섬유소-구연산 병용도포군에서 섬유소양이 대차없이 밀집되어 나타났으며, 술후 3일째부터 대조군과 섬유소 단독도포군에서 상피의 하방성장이 관찰되기 시작하였고 구연산 단독도포군과 섬유소-구연산 병용도포군에서는 상피의 하방성장이 거의 관찰되지 않았다. 술후 1주째부터 각 군의 섬유소가 부분적으로 교원섬유로 대치되기 시작하였으며 2주후 각 군간에 대차없이 대부분의 섬유소기 교원섬유로 대치되는 양상을 보였으며 , 술후 3주째에 구연산 단독도포군과 섬유소-구연산 병용도포군에서 부분적으로 교원섬유의 규칙적인 배열상이 관찰되었고 대조군 및 섬유소 단독도포군에서는 거의 관찰되지 않았다. 구연산 단독도포군과 섬유소-구연산 병용도포군에서는 술후 2주째부터 치근흡수가 관찰되었으며 3주째에는 병 용도포군에 비해 구연산 단독도포군에서 더 많은 치근흡수가 관찰되었다. The purpose of this study was to evaluate the effects of citric acid and fibrin on the regeneration of periodontal tissues using 4 normal canines of five dogs. Mucoperiosteal flap was raised and experimental defects were made at the buccal root surfaces about $4{\times}6mm$ in length. The denuded root surfaces were covered using coronally repositioning technique after root planing alone at left lower canine, root planing plus fibrin at rigth lower canine, root planing plus citric acid at left upper canine or root planning plus citric acid and fibrin at right upper canine. All of the specimens were tangentially cut(about $3-5{\mu}m$)and available for histologic analysis 1, 3, 7, 14 and 21 days after operations. The results were as follows : At one' day after operations, the amounts of fibrin were similarly higher in the group I, II and III than control group and at 3 days after operations, the apical migrations of the long junctional epithelium were prominent in the control group and group I. At 7 days after operations, the fibrin meshworks of each group were partly changed to the collagen fibers and characteristics of the fibers were almost collagenous rather than fibrinous at 14 days after operations and at 21 days after operations, the orientation of collagen fibers were partly normal in group II and group III, but not in control group and group I. Root resorptions were visible in group II and group III at 14 days after operations and more significant in group II than group III at 21 days.

부착면 표면물질에 의한 성능 왜곡을 최소화한 이중 선로의 비대칭 다이폴 형태 태그 안테나 설계

김도균,추호성,Kim, Do-Kyun,Choo, Ho-Sung 한국전자파학회 2007 한국전자파학회논문지 Vol.18 No.4

본 논문에서는 부착될 물질이 가지는 전기적 특성에 의한 성능 변화가 적은 이중 선로의 비대칭 다이폴 형태 RFID 용도 태그 안테나(Asymmetric Dual-arm Dipole Antenna: ADDA)를 제안하였다. 제안된 태그 안테나는 상용 의료 폐기물 수거용 플라스틱 밀폐 용기(${\varepsilon}_r=1.7,\;tan\;{\delta}=0.002$)에 부착하여도 안테나의 동작 특성 변화가 적도록 설계되었다. 안테나의 세부적인 설계변수는 자유공간과 인식 대상 물체에 부착시 우수한 인식거리 성능을 나타내도록 Pareto 유전자 알고리즘을 사용하여 최적화하였다. 최적화 태그 안테나는 $100\;mm{\times}50\;mm$의 크기를 가지며, 3.7 %의 반사 손실 대역폭($S_{11}$< -10 dB)을 가지고 80 %의 복사효율을 나타내었다. 인식 거리 측정 결과, 자유공간에서 정면 방향(broadside) 5.3 m, 의료 폐기물 수거용 플라스틱 밀폐 용기에 부착시 최대 5.5 m의 인식거리 성능을 가지는 것을 확인하였다. In this paper we proposed the tag antenna with a low performance distortion from an attached surface material using the asymmetric dual-arm dipole antenna(ADDA) structure. The tag is designed to exhibit low performance changes when the tag is attached on a target object(the medical litter receptacle, ${\varepsilon}_r=1.7,\;tan\;{\delta}=0.002$). Detail design parameters for the proposed antenna are optimized to maintain a good readable range in free-space as well as on a target object. The size of the optimized antenna is $100\;mm{\times}50\;mm$. The antenna shows the matching bandwidth($S_{11}$< -10 dB) of 3.7 % and the radiation efficiency of 80 % at the operating frequency. Finally we confirmed the readable range of the tag antenna by measurement and it shows about 5.3 m in free space and 5.5 m on the target object.

리듐 2차 전지용 약극활물질 LiFePO₄의 합성 조건에 다른 전기화학적 특성

김도균,박현민,정연욱,이준형,김정주,Kim, Do-Gyun,Park, Hyun-Min,Jeong, Yeon-Uk,Lee, Joon-Hyung,Kim, Jeong-Joo 한국세라믹학회 2006 한국세라믹학회지 Vol.43 No.2

[ $LiFePO_4$ ] is one of the promising materials for cathode material of secondary lithium batteries due to its high energy density, low cost, environmental friendliness and safety. $LiFePO_4$ was synthesized by the solid-state reaction method at 500 - 800°C. The crystal structure of $LiFePO_4$ was analyzed by X-ray powder diffraction. The samples synthesized at 600 and $700^{\circ}C$ showed a single phase of a olivine structure. The particle sizes were increased and the specific surface areas were decreased with heating temperatures. The electrochemical performance was investigated by coin cell test. The discharge capacities at 0.1 C-rate were 118 mAh/g and 112 mAh/g at $600^{\circ}C,\;700^{\circ}C$, respectively. In an attempt to improve the electrical conductivity of cathode materials, $LiFePO_4/graphite$ composite was prepared with various graphite contents. The electrical conductivity and discharge capacity were increased with increasing the graphite contents in composite samples. The rate capabilities at high current densities were also improved.

시뮬레이션 기반 수도권 리사이클링 센터 폐냉장고 전처리 공정 개선

김도균,강민구,최진영,박기진,공만식,Kim, Do Gyun,Kang, Min Koo,Choi, Jin Young,Park, Kiejin,Kong, Man-Sik 한국시뮬레이션학회 2013 한국시뮬레이션학회 논문지 Vol.22 No.4

본 논문에서는 수도권 리사이클링 센터 폐냉장고 전처리 공정의 성능 개선 방안에 관하여 연구하였다. 이를 위해 현행 전처리 공정을 기본 작업 단위로 구분하고 공정 별 작업 시간을 측정하여 ARENA를 이용한 모델링 및 성능 분석을 수행하였다. 또한 실무자의 경험과 선진 사례 등에 기반한 3가지 새로운 전처리 공정 대안을 생성한 후 ARENA를 이용한 모델링 및 시뮬레이션을 통해 평가하였다. 최종 선정된 대안은 현행 2-라인 공정을 1-라인으로 전환하고, 냉매를 회수하기 위한 별도의 셀라인을 도입하는 것을 포함한다. 본 연구 결과는 현재 새로운 전처리 공정 라인으로 설치되어 운영되고 있으며, 이전 공정에 비해 사이클 타임과 생산성 향상뿐만 아니라, 공간 활용률 측면에서도 크게 개선된 결과를 보였다. This paper studies the improvement of a pre-processing line for waste refrigerators in a metropolitan recycling center(MRC). We performed ARENA modeling and simulation by using work analysis and time measurement on the current processing line. Combined this result with some practical experiences from workers, we generated 3 alternatives to improve the current line and evaluated them by using ARENA simulation. The final decision selected consists of changing 2-line process into 1-line and having a separate cell-line for collecting refrigerant. Currently, the result of this study was applied to MRC by improving cycle time, throughput, and space utilization compared to the previous one.

광양만 임해 매립지 느티나무 이식 이후의 연륜생장 특성

김도균,Kim Do-Gyun 한국조경학회 2006 韓國造景學會誌 Vol.33 No.6

This study was carried out to examine the tree-ring growth characteristics of Zelkova serrata Makino after replanting, for the built-up planting founds for stability of landscaped trees in the reclaimed land from the sea. the factors, many affecting the growths of Zelkova serrata Makino, were the replanting stress and drought. The growth reduction due to replanting and drought occurred in the replanting year and the following year. The mean sensitivity(year-to-year variation) and the coefficient of variation(tree-to-tree variation in a certain year) in tree rings of Zelkova serrate Makino, were higher in the poor soil sites than in the favourable soil ones. And the poor soil sites were the filled ground of improve soil and the covered ground of improve soil and the top ground of big mounding than mounding ground sites, especially soil hardness, alkali soil, high $Na^+\;and\;K^+,\;low\;Ca^{++}\;and\;Mg^{++}$ and T-C were the most crucial. We suggest technique development of the built-up planting ground for stability in the reclaimed land from the sea. The built-up planting grounds in reclaimed land from the sea, should be considered for the use of fair soil with the physical and chemical soil properties, -high level foundation of planting ground, and the prevention of disturbed soil-.

전자종이 기술에 관한 연구

김도균,강순덕,Kim, Doh-Gyun,Kang, Soon-Duk 한국정보기술전략혁신학회 2006 情報學硏究 Vol.9 No.3

Electronic paper technology is technology make e- paper, and studying an electronic device is thin like a paper book, an electronic device having made so as to be able to feel as it is feeling of paper like paper newspaper/paper magazines etc. and papers, and crumple freely, or to be able to fold. While electronic paper substitutes for role of paper, a digital function has at the same time a lot of the acids which shall exceed to implement. Necessary, and the continuous researcher who can solve a problem of a fast answer speed for animation implementation, collar implementation and low drive voltage is important a security of a patent right preparing for new market formation, too very in order to form the market where electronic paper can substitute for papers and the existing display as indication elements of a dream, and shall be made to achieve a continuous technical researcher.

탄산아파타이트로 된 인공골과 소뼈에서 유래한 무기질 골의 초기 골전도에 대한 연구

김도균,조태형,송윤미,판휘,이수연,진임건,김인숙,홍국선,황순정,Kim, Do-Kyun,Cho, Tae-Hyung,Song, Yun-Mi,Pan, Hui,Lee, Su-Yeon,Jin, Im-Geon,Kim, In-Sook,Hong, Kug-Sun,Hwang, Soon-Jung 대한악안면성형재건외과학회 2007 Maxillofacial Plastic Reconstructive Surgery Vol.29 No.6

Introduction: Although several types of calcium-phosphate coumpound have been frequently applied to osseous defects at maxillofacial area for many years, there is a controversy about its efficiency on bone conductivity comprared to xenograft bone substitute. Alloplastic carbonapatite has been introduced to improve disadvantages of hydroxyapatite and to mimic natural bone containing carbon elements. However, a preclinical study about its efficiency of osteoconductivity has not been reported. This study was performed to evaluate the early osteoconductive potential of synthetic carbonapatite with multiple pores relative to anorganic bovine xenograft. Materials and methods: Total 5 beagle dogs were used for maxillary augmentation model. The control (anorganic bovine xenograft) and experimental groups (synthetic carbonapatite) were randomly distributed in the mouth split design. After bone graft, all animals were sacrificed 4 weeks after surgery. Histological specimens with Masson Trichrome staining were made and histomorphometrically analysed with image analyser. The statistical analysis was performed using paired t-test. Results: In both groups, all animals had no complications. The experimental group showed relatively much new bone formation around and along the bone substitutes, whereas it was clearly reduced in the control group. The ratios of new bone area to total area, to material area and to the residual area excluding materials were higher in the experimental group ($0.13{\pm}0.03,\;0.40{\pm}0.13,\;0.20{\pm}0.06$ respectively) than in the control group ($0.01{\pm}0.01,\;0.03{\pm}0.02,\;0.03{\pm}0.03$, respectively). And the differences between both groups were statistically significant (p<0.001, <0.01, <0.01, respectively), while the ratio of material area to total area in two groups was not significant. Conclusion: Carbonapatite showed a high osteoconductivity in the early stage of bone healing compared to bovine derived anorganic bone substitute. This study suggests that this bone materials can be applied as a reliable bone substitute in the clinical treatment.

건설회사의 생산성 향상을 위한 조직몰입에 관한연구

김도균,강경식,Kim, Do-Gyun,Kang, Kyung-sik 대한안전경영과학회 2017 대한안전경영과학회지 Vol.19 No.1

This paper provides a basic organizational commitment research for the study was conducted academic research, especially acidic improvements in the construction industry for a job commitment on organizational commitment. In this paper, first results are derived for literature to study and improve productivity and derive a major cause of job involvement of construction companies based on it for critical that the rationale organization.

병해충 분류를 위한 DANet-CAM

웬트리찬흥응 ( Nguyen Tri Chan Hung ),김영언 ( Young Un Kim ),이효종 ( Hyo Jong Lee ) 한국정보처리학회 2022 한국정보처리학회 학술대회논문집 Vol.29 No.2

작물을 경작 해충과 질병은 오랫동안 주요 관심사였다. 농업에서 병해충을 탐지하기 위해 전통적인 방법을 사용하는 것은 더 이상 높은 효율성을 제공하지 않는다. 오늘날 과학과 인공 지능의 폭발적인 발달로 인해 농업분야의 연구원들은 병해충을 탐지하기 위해 딥 러닝을 적용하고 있다. 최근에 다양한 분야의 문제들을 해결하기 위해 수많은 모델들이 발표되었지만, 많은 병해충 진단딥러닝을 사용한 방법들은 하드웨어 리소스를 낭비하고 실제 농장에서 사용하기 어렵다. 따라서 본 논문에서는 작물의 병해충을 분류하기 위해 Select Kernel Attention(SK Attention)을 Channel Attention Module 로 변경하여 Decoupling-and-Attention network (DANet)을 하드웨어 리소스 사용을 최소화한다.