중간 저장조 운영방안을 고려한 비순차 다목적 회분식 공정의 최적조업순서 결정

이호경,김상범,이인범,이의수 한국화학공학회 2001 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.39 No.1

이 논문에서는 다양한 중간 저장조 운영 방안에 따른 비순차 다목적 회분식 공정의 최적 조업 순서 결정을 위한 수학적 모델을 제안한다. 비순차 다목적 회분식 공정에서는 다품종 공정의 경우와 달리 각제품의 제조 경로가 서로 다를 뿐 아니라 역방향 제조 흐름이 존재한다. 따라서, 장치 유휴시간을 줄여 공정의 효율을 높이려면 각 제품의 제조 경로와 중간 저장조 운영 방안을 고려해 각 장치에서 제품 처리 순서를 서로 다르게 결정해야만 한다. 이를 위한 접근 방법으로 주어진 중간 저장조 운영 방안에 대해 각 장치에서 이루어지는 조업의 시작과 완료 시간을 제품과 처리순서 기준으로 각각 표현한 후 이진 변수와 논리적 제약 조건을 이용해 두 표현에 사용된 변수를 일치시켰다. 모델은 혼합정수선형계획법(Mixed Integer Linear Programing, MILP) 형태로 표현되었으며, 세 가지 예제에 적용하여 제안된 모델의 효용성을 보였다. In this paper, we present mathematical models for optimal scheduling of non-sequential multipurpose batch processes under various intermediate storage policies. Compared with multiproduct processes, in non-sequential multipurpose batch processes, the production routes of products may be different from one another and may be backward direction. Consequently, in order to reduce idle time of units and to raise the efficiency of process, we have to make operation sequences of products in each unit differently by considering processing route of each product with a given intermediate storage policy. The basic concept of our approach for these problems is as follows. Firstly, we represented the staging and finishing time of a task in each unit with two coordinates for a given storage policy. One is based on products, and the other is based on sequences. Then, we matched the variables used in the two coordinates into one with binary variables and logical constraints. We formulated these problems as MILP(Mixed Integer Linear Programming) models and apply them to three examples to show the effectiveness of the model.

CATV 역방향 채널의 ATM셀 에러 확률 시뮬레이션

李鎬京 弘益大學校 科學技術硏究所 1998 科學技術硏究論文集 Vol.9 No.2

In this paper, we explains the upstream channel of interactive CATV system and simulate the system performance. In this simulation, we consider the R-S block code and burst mode QPSK modem synchronization. In CATV upstream channel, subscribers share the same frequency band by the time sharing method. To realize this TDMA scheme, we consider the data packet which consist of (53, 59) R-S Coded ATM cell and 4-byte preamble. We present simulation results on cell error rates.

쥐의 망막 미세구조에 미치는 급성 메탄올 중독에 대한 에탄올의 효과 관찰

이호경,유진형,구본술 인제대학교 1983 仁濟醫學 Vol.4 No.3

복강내 메탄올 주입으로 급성 메탄올 중독을 일으킨 쥐와 메탄올 주입 직후, 8시간 후 및 24시간 후에 에탄올을 투여한 쥐의 망막 미세구조를 관찰하여, 메탄올 주입 직후와 8시간 후에 에탄올을 투여한 쥐에서 메탄올에 의한 망막 조직 파괴가 경감되었음을 관찰하였다. Methanol is a widely-used chemical which can cause serious visual loss by accidental ingestion, and ethanol therapy has been considered effective in maintaining life as well as preserving vision, if performed appropriately. To provide histopathologic basis of ethanol therapy in acute methanol poisoning, which is still obscure, methanol was injected intraperitoneally to the rat and ethanol therapy was carried out immediately after, 8 hours after, and 24 hours after methanol injection. One month later, specimens of retina were obtained and examined using electron microscope, comparing with only methanol-injected case. The results were as follows. 1.Ultrastructural examination of retina of the only methanol·injected rat revealed such histologic changes as retinal ganglion cell degeneration, vacuole formation in nerve fiber layer, photoreceptor outer segment destruction, and separation of inter-pigment epithelial junction, which are compatible with clinically observed visual deterioration. 2.Retinal changes were much reduced in the rat which had received ethanol therapy immediately after methanol injection, but the reduction was not conspicuous in the 8 hour-interval ethanol treated rat. No differences were found between only methanol-injected rat and 24 hour-interval ethanol-treated case.

초자제절제술 관류액에 혼합된 Cefazolin 항생제의 안전농도에 관한 실험적 관찰

李虎經,李柱華,柳珍馨 인제대학교 1988 仁濟醫學 Vol.9 No.1

안구내염의 치료에 쓰이는 초자체절제술관류액내의 Cefazolin 항생제의 안전농도 설정의 기초 자료를 마련코자, 유색가토를 사용한 동물실험을 시행하여 전자현미경으로 병리조직학적관찰을 함으로써, 1㎍/ml의 농도에서 안전농도일 가능성을 시사하는 결과를 얻었다. Management of infectious endophthalmitis presents one of the most challenging problems in ophthalmology. Retention of vision even in culture-proven cases has remained consistently poor Recently vitrectomy is introduced into the management of endophthalmitis, often with antibiotics in the infusion fluid, to promote intraocular drug diffusion. In this animal experiment, the author studied ultrastructural changes of the rabbit retina caused by various concentrations of cefazolin mixed in the infusion fluid to help determine the non - toxic concentration. Pars plana core vitrectomy was performed with infusion fluid containing 40, 10. 5, and 1 ㎍/ml cefazolin on the 4 eyes of 4 rabbits respectively. Eyeballs were enucleated 2 weeks after and specimens were immediately processed for transmission electron microscopic examination. Same procedures were repeated using gentamicin to compare with the already known toxicity. Osmolar concentration of each infusion fluid was checked to evaluate the possible high osmolar toxicity. The results were as follows ; 1.In the 40 ㎍/ml group, pyknosis and cytoplasmic degeneration were observed in the inner and outer nuclear layer, and photoreceptor inner segment showed swelling and destruction of organelles, resulting in prominent fiber baskets of Muller cell processes. Retinal pigment epithelium also showed loss of apical microvilli, breaks in the cytopalsm, and widening of basal infoldings. 2.Findings in the 10 and 5 ㎍/ml groups were similar to the 40 ㎍/ml group. 3.In the 1 ㎍/ml group, the changes were reduced but not as normal as in the comparison group. 4.It was confirmed that the changes noticed in the 40. 10, 5, and 1 ㎍/ml groups were not related with high osmolar concentration of the infusion fluid. In comparison with the gentamicin experiment, we may conclude. in spite of the ultrastructural changes noticed in the 1 ㎍/ml group, that these changes are reversble and functionally unharmful, provided that those additional tests such as electroretinography and fluorescein angiography be supplemented. Taking into consideration the mechanism by which cephalosporin makes retinal toxicity, we could suppose that this antibiotics might reach the enzyme-rich retinal cells and inhibit the enzyme-rinked metabolism to make the morphological and functional changes is them.

아르곤 레이저 광응고술에 의한 망막조직 변화의 장기적 관찰

이호경,이주화,유진형 인제대학교 1987 仁濟醫學 Vol.8 No.1

유색가토의 후극부 망막에 청록파장의 아르곤레이저 광선을 조사하여 광응고술을 시행하고 7개월 후에 그 조직병리학적 변화를 광학현미경 및 전자현미경으로 관찰하였다. In order to observe the longterm changes of the rabbit retina produced by the argon laser photocoagulation, we made photocoagulation burn at the posterior pole of the pigmented rabbit eyeball, an area which is so called visual streak and examined its histopathologicalchanges using light and electron microscopes 7 months after photocoagulation. In result, 1.Changes were noticed mainly in the outer retinal layers in which outer and inner segments of the photoreceptors were degenerated or replaced by granular materials and RPE became thinner, depigmented or multilayered by hyperplasia. Outer nuclear layer and RPE were severely destructed in the area where we thought the center of the laser beam had fallen, but the Bruch membrane was intact. 2.These findings were not so different from those of the previous authors who reported 2 month after photocoagulation. 3.We performed ophthalmoscopically strong photocoagulation to produce histopathologically weak to medium intensity burn, which may suggest the inaccuracy of the ophthalmoscopical grading of retinal photocoagulation burns.

[P6-06] 독활(獨活 Aralia continentalis) 추출물의 용매 분획별 항균특성

이호경,방혜연,정숙현 한국식품영양과학회 2006 한국식품영양과학회 학술대회발표집 Vol.2006 No.10

Zero Wait 조업 방식에서의 다품종 생산용 회분식/반연속식 공정의 최적 설계

이호경,정재학,이인범,장근수 한국화학공학회 1994 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.32 No.4

스케줄링을 고려한 회분식 공장의 최적 설계는 초기 자본비를 절감시킨다. 중간저장탱크 조업 방식의 하나인 ZW(Zero Wait)에 대하여 세척시간(cleanup times)과 이동시간(transfer times)을 고려한 스케줄링 방법을 회분식 공장의 설계수식에 첨가함으로써 비선형 프로그램을 이용하여 장치의 최적크기와 생산 순서를 결정하는 방법을 제안한다. 두 개의 예제들을 통하여 본 방법의 효율성을 입증한다. The optimal design of batch plants considering scheduling effects gives us savings of capital cost. Using a nonlinear programming formulation, which includes zero wait scheduling policy with cleanup and transfer times, we propose a method to obtain the optimum size and production sequence. The effectiveness of this method is verified by solving two problems.

[특집/기술해설]TCM 설계 개요 및 성능 분석

이호경,김연형 대한전자공학회 2001 텔레콤 Vol.17 No.2

폴리에테르 폴리우레탄우레아 탄성체의 구조와 형태

이호경,고석원 한국섬유공학회 1993 한국섬유공학회지 Vol.30 No.11

Three sones of polyether polyurethaneurea(PEUU) elastomers based on polytetramethylene glycol (PTMG, MW: 1000 or 2000). 4,4'- diphenylmethane diisocyanate(MDI) and three kinds of diamine chain extenders, i.e., 4.4'-diaminodiphenyl methane(DAM). m-phenylene diamine(MPD) and P-phenylene diamine (PPD) were synthesized. The effect of hard segment structure, hard segment content and block length on the hard domain morphology was studied by using SAXS, stress hysteresis and IR measurements. The samples with lower hard segment content or those with shorter block length at the same hard segment content exhibited more isolated hard domain morphology with diffuse interfacial boundaries. Anisotropic superstructure could be observed by polarized microscopy and TEM, but the size were dependent on the kinds of chain extenders or hard segment contents.

[특집/기술해설] 연속 위상 변조(CPM)를 위한 다중 신호 트렐리스 부호화 변조(TCM) 방식

이호경 대한전자공학회 1994 텔레콤 Vol.10 No.2