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VoIP(Voice over IP)서비스 품질관리 방안 연구
노시춘,김태은 남서울대학교 2009 남서울대학교 논문집 Vol.15 No.2
VoIP service is divided into H.323 related service and SIP related service. Development of multimedia service for VoIP is in the process going beyond the utilization phase of voice service. This research proposes that VoIP QoS can be provided by managing the weakness of VoIP related protocol with design of measurement management process model for VoIP QoS. Furthermore, it proposes the use of analysed item and quality item driven per voice service from VoIP service quality measurement value of the site utilizing VoIP service can increase the quality. This research is finding the meaning and assignment of VoIP QoS to deduct how to manage the control system and presenting the QoS control process and trial framework. The trial framework is the modeling of the QoS measurement metrics, the measurement time schedule, the section, hierarchy, instrument, equipment and method of measurement and the series of cycle & the methodology about analysis of the result of measurement. Measurement result can be used for improvement of VoIP service quality of both service provider and user. However, if end user wants to measure the overall quality, not only IP network to be measured but also the Gateway. To acquire quality of VoIP, continuos development of efficient measurement method and measurement item to clearly indicate the quality level of service and performance of network, and applying of such development is necessary. Keywords : VoIP, QoS, framework
Adipic dihydrazide 말단기 도입에 따른 수분산성 폴리우레탄프리폴리머의 제조와물성
김관영,최희성,노시태 한국공업화학회 2003 응용화학 Vol.7 No.1
Polyurethane dispersions(PUD) were prepared from IPDI, PHMCD, DMPA as anionic site, and ADH as end-capping.This prepolymers were dispersed in the aqueous phase by neutralization emulsification. The polyurethane dispersions were electrostatically stabilized with carboxyl group incorporated into their particles, which were neutralized by TEA(triethylamine).The lhysical properties of aqueous PU prepolymer were investigated by differential scanning calorimetry (DSC), gel permeation chromatography (GPC), dynamic light scattering (DLS), and Rheometer.This procedure contains the effect of molecular weight on the particle size of PUD and on the viscosity were investigated.As the molecular weight of PUDs increascd the particle size and viscosity is not changed.
방향족 폴리에스터 폴리올을 이용한 폴리우레탄 분산체의 합성과 특성에 관한 연구
주훈관,조항규,노시태,강신춘,안재범 한국공업화학회 2004 응용화학 Vol.8 No.1
Aromatic polyurethane dispersions were synthesized with dimethylolpropionic acid (DMPA), isophorone diisocyanate(IPDI), and aromatic polyester polyol, prepared chemical reaction of esterification and polycondensation, The structures of these polyurethanes were characterized by FT0IR, H-NMR, and the properties were measured with DSC, TGA. Increase aromatic polyol contents made of unplasticized polyurethane dispersions. As the aromatic structures in polyurethane dispersions introduced, glass transition temperature(T_(g)) and thermal stability increased. In this polyurethane dispersions increased with DMPA concentrations, particle size decreased and dispersible stability increased and T_(g) increased over 50℃.
연속식 MMA polymer 중합반응기의 Fuzzy FF/FB제어
장원혁,강신춘,노시태 한양대학교 공학기술연구소 1992 공학기술논문집 Vol.1 No.1
A feedforward control law which is efficient in eliminating the effect of measurable disturbances on process outputs is synthesized by a fuzzy modeling. Through analyzing the process operation data sets we constructed the fuzzy model that could calculate the manipulation at steady-state for the load and/or set-point change and designed a feedforward/feedback controller based on it. The designed controller was installed to a CSTR polymerization reactor and its performance was evaluated through simulations.
Glycol Oleates의 합성과 절삭유제로서의 물성
최형기,이호식,이치우,강신춘,노시태 한양대학교 공학기술연구소 1993 공학기술논문집 Vol.2 No.1
Glycololeates for the application of cutting fluid were synthesized from oleic acid and glycols such as ethylene glycol, diethylene glycol and triethylene glycol. The ratio of glycol-monooleate and dioleate in product according to the reaction condition was analyzed by TLC, CC and HPLC. Properties of glycololeates as cutting fluid were examined by various testing methods such as profile test, pH test, anti-foaming test friction coefficient test and emulsion stability test to compare those of base oil and cutting fluid trading in the market. Non-catalytic reaction of glycololeates synthesis was showed too low conversion rate, but too fast conversion rate and deep color deterioration of products was obtained with acid-catalyses reaction. Using the SnCl2 catalyst, conversion rate was medium range and products which suitable for the application of cutting fluid with mild colored and with desirable mono- and di-oleate composition was obtained. Cutting fluidal properties of glycololeates with SnCl2 catalyst were better than those of base oil, and were similar level to those of cutting fluid containing various additives.