• Korean Membrane Journal
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• 제8권1호
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• pp.58-66
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• 2006

The ${\beta}-glucosidase$ from olive fruit is of particular interest compared to the ones from other sources because it has shown to have high specifity to convert the oleuropein into dialdehydes, which have antibacterial activity and are of high interest for their application in the food and pharmaceutical fields. The enzyme is not yet commercially available and advanced clean and safe technologies for its purification able to maintain the functional stability are foreseen. The purification of this protein from fruit extracts has been already tempted by electrophoresis but either enzyme deactivation or high background with unclear profiles occurred. In this work, fruit extracts obtained from the ripening stage that showed the highest enzyme activity have been processed by diafiltration and ultrafiltration. Asymmetric membranes made of polyamide or polysulphone having 50 and 30 kDa molecular weight cut-off, respectively, were tested for the diafiltration process. Ultrafiltration membranes made of polyethersulfone with 4 kDa molecular weight cut-off were used to concentrate the dia-filtered permeate solutions. The efficiency of the separation processes was evaluated byenzyme activity tests using the hydrolysis of p-D-nitrophenyl-${\beta}$-D-glucopyranoside (pNPGlc) as reaction model. Qualitative and quantitative electrophoresis were applied to analyze the composition of protein solution before and after the membrane separation; in addition dot blot and western blot analyses were applied to verify the presence of ${\beta}-glucosidase$ in the processed fractions. The overall results showed that the ${\beta}-glucosidase$ functional stability was preserved during the membrane operations and the removal of 20 kDa proteins allowed to increase the specific activity of the enzyme of about 52% compared to the one present in the initial fruit extract.

• 기본간호학회지
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• 제3권2호
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• pp.259-271
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• 1996

This reserch has been done in order to improve quality of nursing and medical service. In order to improve those qualities the study has been done to know inpatient perception of kindness and meaning of kindness which patients receive from nurse and also what effect inpatient have when they experience kindness from nurse. The subjects were 454 people who admitted in K Hospital. Time period was from October to December 1995. This survey has been done by personal interview with a written questionnaire. Analysis of data has been done by $X^2-test$ and percentage. The results of the research may be summarized as follows. 1. The inpatients perception of kindness on nurse were explanation(26.8%), tolerance(16.3%), warm-heartedness(12.8%), interest(9.5%), ability(8.4%), confidence(6.4%), respect(4.0%), support(2.65%). 2. In order to find out general moaning of kindness, study classified by age, sex, education, job, experience of hospitalization, inpatient ward. As a result of $X^2-test$, no special meaning of kindness was presented in inpatient perception of kindness. 3. Contents kindness which inpatient experienced were, warm-heartedness(23%), understanding(18.1%), interest(17.8%), ability(12.8%), tolerance(5.7%), confidence(2.6%), 4. Over half of subjects(59.1%) answered stability to effect on kindness of Nurse. Next are self-confidence(7.9%), respect(5.3%), confidence(4.6%), warm-heartedness(3.5%), understanding(2.6%). According to above results inpatient feels that meaning of kindness were explanation, tolerance, warm-heartedness. This meaning has no distinctive difference other than consistent meaning. Likewise, inpatient experience about contents of kindness is similar to meaning of kindness. As a result of this research, which show that kindness of nurse gives patient stability, respect and confidence, we would kindness is important for recovery of inpatient. Therefore, this research outcome could be able to help to improve quality of nursing and medical service.

• 융합정보논문지
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• 제9권5호
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• pp.217-227
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• 2019

본 연구는 DISC행동유형에 따른 전공만족도와 직업선호도와의 관계를 파악하기 위하여 시행하였다. 2019년 4월 1일부터 10일까지 치위생(학)과 학생 192명을 대상으로 설문조사를 실시하였다. 분석 결과, DISC행동유형에 따른 전공만족도의 하위요인 중 수업내용, 교수지도방법에서 S형이 높았고, 학교시설 및 환경은 C형과 S형이 높았다. DISC행동유형에 따른 직업선호도는 하위요인 중 명예, 발전성과 안정성 선호도에서 D형이 높았다. 적성과 흥미, 발전성과 안정성, 근무환경 선호도는 S형이 높았으며, 적성과 흥미는 C형에서 높았다. DISC행동유형과 전공만족도, 직업선호도는 서로 관련이 있는 것으로 확인된 바, 대학생의 진로지도 시 고려하여야 할 것으로 생각된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.700-705
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• 2005

The purpose of this project is the derivation and development of techniques for the new estimation of robustness for the systems having uncertainties. The basic ideas to analyze the system which is the originally nonlinear is Lyapunov direct theorems. The nonlinear systems have various forms of terms inside the system equations and this investigation is confined in the form of bounded uncertainties. Bounded means the uncertainties are with same positive/negative range. The number of uncertainties will be the degree of freedoms in the calculation of the stability region. This is so called the robustness bounds. This proposition adopts the theoretical analysis of the Lyapunov direct methods, that is, the sign properties of the Lyapunov function derivative integrated along finite intervals of time, in place of the original method of the sign properties of the time derivative of the Lyapunov function itself. This is the new sufficient criteria to relax the stability condition and is used to generate techniques for the robust design of control systems with structured perturbations. Using this relaxing stability conditions, the selection of Lyapunov candidate function is of various forms. In this paper, the quadratic form is selected. this generated techniques has been demonstrated by recent research interest in the area of robust control design and confirms that estimation of robustness bounds will be improved upon those obtained by results of the original Lyapunov method. In this paper, the symbolic algebraic procedures are utilized and the calculating errors are reduced in the numerical procedures. The application of numerical procedures can prove the improvements in estimations of robustness for one-and more structured perturbations. The applicable systems is assumed to be linear with time-varying with nonlinear bounded perturbations. This new techniques will be extended to other nonlinear systems with various forms of uncertainties, especially in the nonlinear case of the unstructured perturbations and also with various control method.

• Transactions on Electrical and Electronic Materials
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• 제18권5호
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• pp.287-297
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• 2017

Novel power system stabilizers (PSSs) have been proposed to effectively dampen low frequency oscillations (LFOs) in multi-machine power systems and have attracted increasing research interest in recent years. Due to this attention, recently, fractional order controllers (FOCs) have found new applications in power system stability issues. Here, a tilt-integral-derivative power system stabilizer (TID-PSS) is proposed to enhance the dynamic stability of a multi-machine power system by providing additional damping to the LFOs. The TID is an extended version of the classical proportional-integral-derivative (PID) applying fractional calculus. The design of the proposed three-parameter tunable TID-PSS is systematized as a nonlinear time domain optimization problem in which the tunable parameters are adjusted concurrently using a modified group search optimization (MGSO) algorithm. An integral of the time multiplied squared error (ITSE) performance index is considered as the objective function. The proposed stabilizer is simulated in the MATLAB/SIMULINK environment using the FOMCON toolbox and the dynamic performance is evaluated on a 3-machine 6-bus power system. The TID-PSS is compared with both classical PID-PSS (PID-PSS) and conventional PSS (CPSS) using eigenvalue analysis and time domain simulations. Sensitivity analyses are performed to assess the robustness of the proposed controller against large changes in system loading conditions and parameters. The results indicate that the proposed TID-PSS provides the better dynamic performance and robustness compared with the PID-PSS and CPSS.

• 터널과지하공간
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• 제23권2호
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• pp.87-98
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• 2013

국토의 70%가 산지인 우리나라는 도로건설 등에 필요한 토지가 매우 부족할 뿐만 아니라 환경에 대한 국민들의 관심이 고조되어 터널 시공이 증가하는 추세이다. 남해고속도로 냉정~부산간 확장공사 대동1터널 시공 시 계곡부 위치 및 갱문 이격으로 저토피가 발생하였고, 민원 등으로 착공이 지연되어 관통부 변경이 불가피하였다. 이에 다중TSP를 적용하여 관통부 위치를 변경하였고 안정해석을 실시하였다. 해석결과 터널의 안정성에 문제가 없는 것으로 나타났으며, 시공 중 추가적인 안정성을 확보하고자 계측기 설치 및 기계굴착, 저토피 구간 추가 보강, 반단면 굴착을 실시하였다.

• Structural Engineering and Mechanics
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• 제75권5호
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• pp.541-557
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• 2020

A novel family of controllable, dissipative structure-dependent integration methods is derived from an eigen-based theory, where the concept of the eigenmode can give a solid theoretical basis for the feasibility of this type of integration methods. In fact, the concepts of eigen-decomposition and modal superposition are involved in solving a multiple degree of freedom system. The total solution of a coupled equation of motion consists of each modal solution of the uncoupled equation of motion. Hence, an eigen-dependent integration method is proposed to solve each modal equation of motion and an approximate solution can be yielded via modal superposition with only the first few modes of interest for inertial problems. All the eigen-dependent integration methods combine to form a structure-dependent integration method. Some key assumptions and new techniques are combined to successfully develop this family of integration methods. In addition, this family of integration methods can be either explicitly or implicitly implemented. Except for stability property, both explicit and implicit implementations have almost the same numerical properties. An explicit implementation is more computationally efficient than for an implicit implementation since it can combine unconditional stability and explicit formulation simultaneously. As a result, an explicit implementation is preferred over an implicit implementation. This family of integration methods can have the same numerical properties as those of the WBZ-α method for linear elastic systems. Besides, its stability and accuracy performance for solving nonlinear systems is also almost the same as those of the WBZ-α method. It is evident from numerical experiments that an explicit implementation of this family of integration methods can save many computational efforts when compared to conventional implicit methods, such as the WBZ-α method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권12호
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• pp.4411-4431
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• 2014

Mobile ad hoc networks (MANETs) have recently gained increased interest due to the widespread use of smart mobile devices. Group communication applications, serving for better cooperation between subsets of business members, become more significant in the context of MANETs. Multicast routing mechanisms are very useful communication techniques for such group-oriented applications. This paper deals with multicast routing problems in terms of stability and scalability, using the concept of stable core. We propose LMRSC (Lightweight Multicast Routing Based on Stable Core), a lightweight multicast routing technique for MANETs, in order to avoid periodic flooding of the source messages throughout the network, and to increase the duration of multicast routes. LMRSC establishes and maintains mesh architecture for each multicast group member by dividing the network into several zones, where each zone elects the most stable node as its core. Node residual energy and node velocity are used to calculate the node stability factor. The proposed algorithm is simulated by using NS-2 simulation, and is compared with other multicast routing mechanisms: ODMRP and PUMA. Packet delivery ratio, multicast route lifetime, and control packet overhead are used as performance metrics. These metrics are measured by gradual increase of the node mobility, the number of sources, the group size and the number of groups. The simulation performance results indicate that the proposed algorithm outperforms other mechanisms in terms of routes stability and network density.

• Preventive Nutrition and Food Science
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• 제21권3호
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• pp.289-295
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• 2016

Curcumin is a flavonoid found in the rhizome of the turmeric plant (Curcuma longa L.) and has recently attracted interest because it has numerous biological functions and therapeutic properties. In the present study, we attempted to incorporate curcumin into medium-chain triglyceride (MCT) nanoemulsions (0.15 wt% curcumin, 10 wt% MCT oil, and 10 wt% emulsifiers) with various emulsifiers [polyoxyethylene (20) sorbitan monolaurate (Tween-20), sorbitan monooleate (SM), and soy lecithin (SL)]. The physicochemical properties of the nanoemulsions including the Ostwald ripening stability were investigated. The initial droplet size was found to be 89.08 nm for the nanoemulsion with 10 wt% Tween-20 (control), and when Tween-20 was partially replaced with SM and SL, the size decreased: 73.43 nm with 4 wt% SM+6 wt% Tween-20 and 67.68 nm with 4 wt% SL+6 wt% Tween-20 (prepared at 15,000 psi). When the nanoemulsions were stored for 28 days at room temperature, the droplet size increased as the storage time increased. The largest increase was observed for the control nanoemulsion, followed by the 4 wt% SL+6 wt% Tween-20 and 4 wt% SM+6 wt% Tween-20 systems. The Turbiscan dispersion stability results strongly supported the relationship between droplet size and storage time. The time-dependent increase in droplet size was attributed to the Ostwald ripening phenomenon. Thus, the Ostwald ripening stability of curcumin-loaded MCT nanoemulsions with Tween-20 was considerably improved by partially replacing the Tween-20 with SM or SL. In addition, curcumin may have acted as an Ostwald ripening inhibitor.

• 대한기계학회논문집A
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• 제34권3호
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• pp.283-289
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• 2010

친환경기술과 신재생 에너지 자원에 대한 세계적인 관심이 증가하면서, 플라이휠 에너지 저장 장치는 화학전지나 연료전지와 같은 기존의 에너지 저장 시스템의 대안 중 하나로 부상하고 있다. 플라이휠 에너지 저장장치의 에너지 저장 용량은 극질량 관성모멘트와 회전속도의 제곱에 비례하기 때문에, 가능한 높은 회전속도와 높은 극질량 관성모멘트를 갖도록 설계하는 것이 중요하다. 하지만, 시스템의 운전안정성 확보가 최적설계의 구속조건으로 작용할 수 있다. 본 논문에서는 에너지 저장 용량을 최대화하고 운전안정성 및 외란에 대한 강인성을 확보하는 플라이휠 시스템의 최적설계를 제안한다. 그리고, 기존의 PD 제어에 비교하여 교차궤환제어법이 자이로스코프효과를 줄이고, 에너지 저장밀도를 높이는데 필수적임을 확인하였다.