• 한국식품위생안전성학회지
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• 제14권1호
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• pp.84-89
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• 1999

Octenylscuccinated corn starches prepared by reaction of corn starch with 1-octenylsuccinic anhydride(OSAn) and their degree of substitution (DS), reaction efficiency(RE), residual octenylsuccinic acid (OSA), and physicochemical properties were compared with those of the native corn starch. DS increased with increase of OSAn and RE was much nearly the same regardless of increased of OSAn. The content of residual of residual OSA was significantly lower than that of regulation of food additives. And as washing frequency of dispersion of the reactant was increased, the content of residual OSA of octenylsuccinated starch was decreased. Raid Visco-Analyzer initial pasting temperature and setback of octenylsuccinated starches decreased whereas peak viscosity and breakdown increased. When DS of octenylsuccinated starches increased, temperature of initial gelatinization of octenylscuccinated starches drastically decreased. The octenylsuccinated starches also formed clearer pastes. The solubility was much nearly the same regardless of increase of DS at 7$0^{\circ}C$ but the swelling power increased 1.2~1.7 times higher than that of native corn starch at 7$0^{\circ}C$. The water binding capacity of octenylsuccinated starches also decreased.

• 대한치과의사협회지
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• 제48권3호
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• pp.178-183
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• 2010

Obstructive Sleep Apnea(OSA) is a form of sleep disordered breathing(SDB) characterized by the occurrence of episodes of complete or partial upper airway obstruction during sleep that is often quantified as the apnea-hyponea index(AHI). It is increasingly being recognized that OSA is a public health hazard and there is increasing evidence that it is associated with an increase in morbidity. Early recognition and diagnosis of this condition may lead to earlier treatments (eg, CPAP, Oral appliances) with reduction of the risk of metabolic disease, cardiovascular diseases, such as hypertension, ischemic heart disease, arrhythmias and pulmonary hypertension.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.464-469
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• 2005

Optimum sensitivity analysis (OSA) is the process to find the sensitivity of optimum solution with respect to the parameter in the optimization problem. The prevalent OSA methods calculate the optimum sensitivity as a post-processing. In this research, a simple technique is proposed to obtain optimum sensitivity as a result of the original optimization problem, provided that the optimum sensitivity of objective function is required. The parameters are considered as additional design variables in the original optimization problem. And then, it is endowed with equality constraints to penalize the additional variables. When the optimization problem is solved, the optimum sensitivity of objective function is simultaneously obtained as Lagrange multiplier. Several mathematical and engineering examples are solved to show the applicability and efficiency of the method compared to other OSA ones.

• 대한치과의사협회지
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• 제57권5호
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• pp.279-287
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• 2019

Obstructive sleep apnea syndrome (OSAS) is characterized by obstructive events of the upper airway (UAW) during sleep, which can be associated with clinical signs and symptoms such as snoring, excessive daytime sleepiness, impaired memory, and fatigue. It is associated with many problems like psychosocial problems, physiologic alterations in the cardiovascular and respiratory systems as a result of hypoxia and repeated awakenings during sleep. Conservative treatments such as weight loss, sleep positioning, improvement of sleep hygiene, CPAP and MAD can be performed for the obstructive sleep apnea. However, their effect for the OSA is limited and differs by patient's individual properties. Accordingly, surgical reconstructions of the upper airway must be carried out for the treatment of OSA.

• 대한치과교정학회지
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• 제30권3호
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• pp.287-296
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• 2000

OSA가 의심되는 환자에 대하여 수면 다원 검사를 시행하여 RDI가 5이상이고 Arousal Index가 20이상이어서 OSA로 진단된 환자 24명을 무작위로 선택하여 구내장치에 대한 반응검사를 위한 수면검사를 다시 시행하여 장치 장착 전후의 RDI의 변화를 기록하였다. 구내장치 장착전과 후에 두장의 두부 방사선을 호기 말에서 채득하여 안모 형태에 대한 변수를 첫번째 두부 방사선상에서 측정하였고, 두 장의 두부 방사선사진을 중첩하여 연구개,후 인두벽, 혀, 설골, 상기도, 하악의 구내장치에 의한 이동을 나타내는 두부 방사선상의 변수를 측정하였다. RDI 개선도에 따라 가장 양호하게 반응하는 8명과 가장 효과가 낮게 반응하는 8명을 선택하여 두 군으로 분류하여 군 비교를 시행하였다. 군 비교를 위하여 Wilcoxon rank test를 시행 하였고 구내장치에 의한 각 변수의 차이와 RDI 개선도와의 상관관계, 안모 형태와 RDI 개선도와의 상관관계를 알아보기 위하여 Spearmann correlation analysis를 시행하였다. 본 연구의 결론은 다음과 같다. 본 연구에서 사용되어진 구내장치는 장착전 평균 RDI=45.8에서 장착 후 평균 RDI=13.3으로 감소하는 효과를 나타냈고 상관 관계에 있어서 하악의 전방이동량과 설골의 상방 이동량은 구내장치 효과와 유의성 있는 상관관계를 나타냈다. 치료 효과가 양호한 군에서 연구개 끝과 후두 덮개 사이 수준(level)에서 유의성 있는 혀의 전방 이동이 관찰되었으며 이러한 구내장치에 의한 혀의 전방 이동은 RDI 개선도와도 유의성 있는 상관관계를 나타냈다. 연구개 끝과 후두 덮개사이 수준(level)에서 상기도의 전후방 길이인 AW는 RDI 개선도와 유의성 있는 상관관계를 나타냈다. 본 연구에 의하면 혀의 전방 이동과 설골의 상방 이동, 상기도의 전후길이 증가등은 RDI의 양호한 개선을 나타내는 지표 였다.

• Journal of Oral Medicine and Pain
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• 제42권1호
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• pp.1-7
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• 2017

Purpose: The aims of this study were to evaluate the clinical characteristics and polysomnographic results of patients visited the Seoul National University Dental Hospital (SNUDH) and to suggest guidelines for the management of sleep disordered-breathing patients in a dental clinic. Methods: Five hundred sixty-two patients who visited the Snoring and Sleep Apnea Clinic of SNUDH were evaluated for clinical characteristics including associated comorbidities, age, gender, body mass index (BMI), neck circumference, and daytime sleepiness and among them 217 patients were performed nocturnal polysomnography for evaluating respiratory disturbance index, apnea-hypopnea index (AHI), oxygen saturation levels, and sleep stages. The associations among clinical characteristics, sleep parameters, and positional and rapid eye movement (REM) dependencies of the patients were analyzed. Results: The most common co-morbidities of the patients were cardiovascular (30.2%), endocrine (10.8%), and respiratory diseases (7.9%). Age (${\beta}=0.394$), total AHI (${\beta}=0.223$), and lowest $O_2$ saturation levels (${\beta}=0.205$) were significantly associated with the number of co-morbidities in patients with obstructive sleep apnea (OSA). Mean $O_2$ saturation was not significantly associated with number of co-morbidities. Non-positional OSA patients had higher BMI, longer neck circumferences, more severe AHI values, and lower mean and lowest $O_2$ saturation levels compared to positional OSA patients. Not-REM-related patients were older and had more severe AHI values compared to REM-related patients. Not-REM-related patients have longer duration of stage I sleep and shorter stage II, III, and REM sleep than REM-related patients. There were no significant differences in each sleep stage between positional and non-positional patients. Neck circumference, positional dependency, REM dependency, and percentage of supine position were significantly associated with severity of OSA. Conclusions: Age, total AHI, and lowest $O_2$ saturation level were significantly associated with the number of co-morbidities in patients with OSA. Neck circumference, positional dependency, REM dependency, and percentage of supine position were significantly associated with severity of OSA.

• East Asian mathematical journal
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• 제27권1호
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• pp.23-33
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• 2011

Due to underutilization of spectrum under current inefficient and static spectrum management policy, various kinds of opportunistic spectrum access (OSA) strategies have appeared. Myopic policy is a simple and robust OSA strategy with reduced complexity that maximizes immediate throughput. In this paper, we propose mathematical models to evaluate the throughput and the MAC delay of a myopic policy under saturation tra c conditions. Using the MAC delay distribution, we evaluate the packet delay of secondary users under nonsaturation conditions. Numerical results are given to show the performance of the myopic policy in cognitive radio networks.

• Journal of applied mathematics & informatics
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• 제29권5_6호
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• pp.1295-1302
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• 2011

We present an analytic model of an unslotted opportunistic spectrum access (OSA) network and evaluate its performance such as interruption probability, service completion time, and throughput of secondary users. Numerical examples are given to show the performance of secondary users in cognitive networks. The developed modeling and analysis method can be used to evaluate the performance of various OSA networks.

• 광학과기술
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• 제2권1호
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• pp.72-73
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• 1998

• 한국통신학회논문지
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• 제39C권7호
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• pp.546-551
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• 2014

본 논문에서는 릴레이 기반의 선박 통신 네트워크에서 데이터 전송률을 높이기 위한 기회주의적 서브채널 할당기법을 제안한다. 릴레이 시스템을 기반으로 하는 기존 연구에서, 릴레이는 매 프레임마다 기지국으로부터 수신 받은 데이터를 선박에게 즉시 전달 해준다. 이때, 이중 홉 네트워크(기지국과 릴레이, 릴레이와 선박 간 링크)에서 전송 가능한 최대 수율은 두 링크의 채널 상태에 의해 결정된다. 만약, 채널 상태에 따른 두 링크가 가지는 채널 용량의 차이가 크다면 자원이 낭비되는 상황이 발생하게 된다. 이러한 문제점은 시스템의 성능을 저하시키며, 제한된 무선 자원을 효율적으로 활용하지 못하는 문제점이 발생하게 된다. 따라서 본 논문에서는 두 링크 사이에서 발생하는 자원의 낭비를 최소화 시킴과 동시에 자원을 효율적으로 할당 할 수 있는 기법을 제안한다. 또한 제안하는 기법의 계산 복잡도를 줄이기 위해서 차선의 기법을 제안한다. 시뮬레이션 결과를 통해서, 제안하는 기법은 기존 연구 대비 계산의 복잡도는 증가하지만 시스템의 데이터 전송률 성능이 최대 14.0% 향상됨을 확인 할 수 있다.