• 융합보안논문지
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• 제10권1호
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• pp.55-61
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• 2010

소프트웨어 제품을 개발하여 테스팅을 거친 후 사용자에게 인도하는 시기를 결정하는 일은 아주 실제적이고 흥미 있는 일이 된다. 이러한 문제를 소프트웨어 최적 방출시기라고 한다. 본 연구에서는 소프트웨어의 결함을 제거하거나 수정 작업 중에도 새로운 결함이 발생될 가능성이 있는 무한고장수를 가진 비동질적인 포아송 과정에 기초하고 고장간격 수명 시간의 형태에 따른 방출시간의 비교에 대하여 연구되었다. 소프트웨어 요구 신뢰도를 만족시키고 소프트웨어 개발및 유지 총비용을 최소화시키는 최적 소프트웨어 방출 정책이 된다. 본 논문의 수치적인 예에서는 모의실험 자료 즉, 강도함수가 일정한 경우, 증가하는 경우, 감소하는 경우를 적용하여 최적 방출시기를 추정하고 그 결과를 나열 하였다.

• Archives of Pharmacal Research
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• 제10권2호
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• pp.88-93
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• 1987

Chitosan ($\beta$-D-glucosaminan) is chemically prepared from chitin (N-acetyl-$\beta$- D-glucosaminan) which is an unutilized natural resource. We now report on the suitability of the chitosan matrix for use as vehicles for the controlled release of drugs. Salicylic acid and aspirin were used as model drugs in this study. The permeation of salicylic acid in the chitosan membranes was determined in a glass diffusion cell with two compartments of equal volume. Drug release studies on the devices were conducted in a beaker containing 5% sodium hydroxide solution. Partition coefficient (Kd) value for acetate membrane (472) is much greater than that for fluoro-perchlorate chitosan membrane (282). Higher Kd value for acetate chitosan membrane appears to be inconsisstent with the bulk salicylic acid concentration. The permeability constants of fluoro-perchlorate and acetate chisotan membranes for salicylic acid were 3.139 ${\times}10^{-7}cm^2$ min up to 60 min and that of 30% aspirin in the devices was 4.739${\times}10^{-7}cm^2$sec upto 60 min. As the loading dose of aspirin in a chitosan device increased, water up-take of chitosan device increased, but in case of salicylic acid it decreased. The release rate increased with increase in the molecular volume of the drugs. Thses result suggest that the release mechanism may be controlled mainly by diffusion through pores.

• Journal of Pharmaceutical Investigation
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• 제17권3호
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• pp.111-126
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• 1987

Methyl methacrylate-butyl methacrylate copolymer (MMBM)-dibutyl phthalate (DBP) films were investigated as a potential topical drug delivery system for the controlled release of nitrofurazone. The kinetic analysis of release data indicated that drug release followed a diffusion-controlled granular matrix model, where the quantity released per unit area is proportional to the square root of time. DBP of several hydrophobic plasticizers selected was found to give the highest release of nitrofurazone. However, hydrophilic plasticizers such as propylene glycol and polyethylene glycol 400 had no controlled release properties and acceptable film formation. The effects of changes in film composition, drug concentration, film thickness, pH of release medium, and temperature on the in vitro release of nitrofurazone were analyzed both theoretically and experimentally. The release rate constant (k') was found to be proportional to DBP content, pH, and the temperature of release medium, but independent of film thickness, and drug concentration in a range of 0.1-0.4% by weight. The linear relationship was found to exist between the log k' and DBP content. The release of nitrofurazone from MMBM-DBP (8:2) films was found to be an energy-linked process. Two energy terms were calculated ; the activation energy for matrix diffusion was 13.45 kcal/mole, and the heat of drug crystal solvation was 27.26-29.34 kcal/mole. Observation of scanning electron micrographs and microscopic photographs showed that the incorporation of DBP in films increased markedly the particle size of nitrofurazone dispersed in the film matrix, comparing with the fine dispersion of nitrofurazone in pure MMBM film alone.

• 한국환경농학회지
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• 제30권2호
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• pp.144-152
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• 2011

본 연구는 주암호 홍수조절용지내에 서식하는 침수식물체들의 영양염류 용출이 주암호 수질에 미치는 영향을 조사하고자 침수상태의 수질, 토양 및 식물체를 자연상태 그대로 column으로 옮겨와 침수기간별 영양염류의 제거속도 및 용출속도를 조사하였고, 이들 결과를 토대로 각 홍수조절용지에서 침수식물체별 영양염류 용출량을 산출하였다. COD 제거속도 상수(K, $day^{-1}$)는 이삭사초의 경우 침수 0~4 day, 5~19 day 및 20~33 day 구간에서 0.07~0.18, -0.23~-0.17 및 -0.28~0.03 $day^{-1}$이었고, 물억새의 경우 침수 0~6 day, 7~19 day 및 20~33 day 구간에서 0.14~0.22, -0.19~-0.04 및 -0.05 $day^{-1}$이었다. T-N 제거속도 상수(K, $day^{-1}$)는 이삭사초의 경우 침수 0~4(8) day 및 5(9)~33 day 구간에서 0.02 및 -0.13~-0.10 $day^{-1}$이었고, 물억새의 경우 침수 0~2(4) day, 3(5)~19 day 및 20~33 day 구간에서 0.01~0.04, -0.03 및 -0.18~-0.17 $day^{-1}$이었다. T-P 제거속도 상수(K, $day^{-1}$)는 이삭사초의 경우 침수 0~4 day 및 5~33 day 구간에서 0.05~0.06 및 -0.14~-0.09 $day^{-1}$이었고, 물억새의 경우 침수 0~4 day 및 5~33 day 구간에서 0.05~0.06 및 -0.15~-0.12 $day^{-1}$이었다. 이상의 결과에서 침수초기에는 침수식물체가 생육하면서 영양염류를 분해 이용하여 수질을 정화하였으나, 침수식물체에 따라 다소 차이가 있었지만 침수 4~10일후부터 침수식물체가 미생물에 의해 서서히 분해되면서 영양염류가 수질내로 용출되는 경향이었다. 홍수조절용지에서 침수식물체별 영양염류용출량은 이삭사초가 물억새에 비해 약간 많았다. 특히 site 1에서 COD, T-N 및 T-P 용출량은 이삭사초의 경우 각각 6,719, 2,397 및 466 kg/month/area이었고, 물억새의 경우 각각 53.1, 14.8 및 3.30 kg/month/area이었다.

• 전자공학회논문지
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• 제52권1호
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• pp.24-31
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• 2015

코드워드의 인자로 M진 위상 편이 방식(M-ary phase shift keying, M-PSK)를 사용하는 차분 코드북은 Long term Evolution (LTE), LTE-Advanced (LTE-A) 그리고 WiMax 시스템 등에 제안된다. 인접하는 무선 채널의 시간 상관 특성에 의해 연속된 선부호화 행렬 내 양자화된 채널 정보는 천천히 변화된다. 이는 전체 무선 채널 공간을 양자화 하지 않고, 시간 상관 특성에 따른 채널 공간 내 일부분만을 양자화하여 피드백하기 때문에 기존과 동일한 크기의 코드북을 구성해도 가상적으로 보다 정확한 채널정보를 양자화할 수 있어 채널 용량이 증가하는 효과를 갖는다. 제안하는 코드북은 constant modulus, complexity reduction, 그리고 nested property와 같은 LTE release-8 코드북 특성을 갖는다. 또한 동 이즉 전송 특성을 갖기 때문에 상대적으로 저렴한 비선형 증폭기를 사용할 수 있어 가격의 제한을 받는 단말기 설계에도 이점을 갖는다. 컴퓨터 시뮬레이션을 통해 제안하는 차분 동 이득 전송 기술은 동일한 피드백 비트 수를 갖는 기존의 LTE-8 코드북보다 향상된 성능을 보인다.

• Archives of Pharmacal Research
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• 제13권2호
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• pp.151-160
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• 1990

In order to develop a controlled-release oral drug delivery system (DDS) which sustains the plasma acetaminophen (AAP) concentration for a certain period of time, microporous membrane-coated tablets were prepared and evaluated in vitro. Firstly, highly water-soluble core tablet of AAP were prepared with various formulations by wet granulation and compression technique. Then the core tablets were coated with polyvinychloride (PVC) in which micronized sucrose particles were dispersed. Effect of formula compositions of core tablets and coating suspensions on the pharmaceutical characteristics such as drug release kinetics and membrane stability of the coated tablets was investigated in vitro. AAP was released from the coated tablets as a zero-order rate in a pH-independent manner. This independency of AAP release to pH change from 1.2 to 7.2 is favorable for the controlled oral drug delivery, since it will produce a constant drug release in the stomach and intestine regardless of the pH change in the GI tract. Drug release could be extended upto 10 h according to the coating condition. The release rate could be controlled by changing the formula compositions of the core tablets and coating suspensions, coat weight per each tablet, and especially PVC/sucrose ratio and particle size of the sucrose in the coating suspension. The coated tablets prepared in this study had a fairly good pharmaceutical characteristics in vitro, however, overall evaluation of the coated tablet should await in vivo absorption study in man.

• 한국자동차공학회논문집
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• 제1권1호
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• pp.50-58
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• 1993

The ignition delay of diesel oil and fish oil blended with diesel oils was investigated at various pressure and temperature conditions in a constant volume combustion bomb. The evaporation and combustion duration of diesel oil and fish oil blended with diesel oils were respectively different in high and low temperature. The dependence of ignition delay on the temperature was different in high and low temperature ranges which were divided at the 773K. The dependence of ignition delay on the pressure was almost linear, regardless of the test fuels at the constant temperature(863K). The ignition delay became longer as the blending rate of fish oil increased at the constant temperature and pressure, but it was especially short with 20% fish oil blended with diesel oils.

• Clinics in Shoulder and Elbow
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• 제21권3호
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• pp.127-133
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• 2018

Background: This study was undertaken to evaluate the outcome of the arthroscopic capsular release for adhesive capsulitis of the shoulder. Methods: This study retrospectively investigated thirty shoulders in 29 patients who presented with recalcitrant adhesive capsulitis and underwent arthroscopic treatments. Other than typical findings of adhesive capsulitis, combined pathologies in the glenohumeral joint and subacromial space were evaluated by arthroscopy. Clinical evaluations were performed using the Constant's score and ranges of motion (ROM) at preoperative, 6 months postoperatively and at the final follow-up. Results: Our study included 17 women and 12 men with a mean age of 53.8 years (range, 34-74). Mean follow-up duration was 24 months (range, 12-40 months). Assessment of combined pathologies revealed that partial rotator cuff tear of less than 25% thickness, was most common (overall 83.3%; with bursal 57% and articular 23%). Subacromial synovitis and adhesion were also frequent (53.3%). The Constant score and ranges of motion significantly improved at the final follow-up, compared with preoperative levels. However, clinical results at 6 months postoperatively were found to be significantly inferior to those observed at the final follow-up ($p{\leq}0.001$ for all factors). Functional impairment was the major complaint in 59.3% patients at the 6 months follow-up. Conclusions: Although arthroscopic capsular release yielded favorable outcome at the mean 24 months follow-up, pain and motion limitations at 6-month postoperatively persisted in more than 50% of our patients. While combined pathologies were commonly encountered during arthroscopy, although their effects on surgical outcome in adhesive capsulitis remains unclear in this study.

• KSBB Journal
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• 제11권6호
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• pp.676-680
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• 1996

키토산을 10%-아세트산에 팽윤시킨 용액과 SD 를 인산염 완충용액에 녹인 용액을 흔합하여 키토산 매트릭스를 제조하였다. 키토산 매트릭스로부터 pH 7 7.4와 pH 1.2에서 약물방출 거통을 규명하고 지속적이고 조절된 약물방출형 제제로서의 사용 가능성 을 고찰하였다. 키토산 매트릭스내의 약물 함유량이 증가함에 따 라 약물 방출 시간이 늦어졌으며, pH 1.2에서보다 p pH 7.4에서 약물 방출 시간이 더 지연되었다. 그 이 유는 약물전달체가 엽기성 용액에서보다 산성 용액 에서 팽윤를 더 잘하기 때문이라고 생각된다. 약물 방출 속도에 있어서는 pH 7.4에서보다 pH 1.2에서 더 빨랐으며, 겉보기 방출속도상수(K)값도 역시 증가하였다. 결과적으로 본 실험에셔 약물전달체로 사 용된 키토산은 방출조절형 제제로서 그 가능성을 타진할 수 있었다.

• Archives of Pharmacal Research
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• 제8권1호
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• pp.7-14
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• 1985

Membrane-coated tablet of isonicotinic acid hydrazide (INAH) which releases INAH at the zero-order kinetics was deveoped. It consisted of a soluble tablet core surrounded by a porous membrane which controls the diffusion rate. Tablet cores were prepared by compressing granules of INAH and polyvinyl chloride (PVC) dissolved in methyl ethyl ketone in which micronized sucrose were suspended. Diffusion rate of INAH from the tablet through the membrane was constant until the loaded INAH in the core was almost released. The rate was independent of pH of the dissolution medium. Water-soluble sucrose particles behaved as a poreproducing material in the water-insoluble PVC film coat. The pH independency of the rate was probably due to the high solubility of INAH in the water of wide pH range. The diffusion rate of INAH could be controlled by chnaging the composition of the membrane or the coat weight. This membrane-coated INAH tablet seemed to be a powerful candidate for the controlled release drug delivery system (DDS) of INAH or other highly watersoluble drugs.