• Journal of the Korea Institute of Military Science and Technology
• /
• v.20 no.1
• /
• pp.25-32
• /
• 2017

Most of weapon systems use aided navigation system which integrates inertial navigation and aiding sensors to compensate the INS errors increasing with the passage of time. Various aid sensors can be applied such as Global Navigation Satellite System (GNSS), radar, barometer, etc., but there might exist time delay caused by signal processing or transferring aid information. This time delay leads out-of-sequence measurements (OOSM) systems. Previously, optimal and suboptimal measurment update method for OOSM systems, where the time delay length are known, are proposed. However, previous algorithm does not guarantee the positive definite property of covariance matrix. In order to improve numerical stability for aided navigation using delayed-measurement, this paper proposes a new measurement covariance update algorithm be similar to Joseph-form in Kalman filter. Futhermore, we propose how to implement it in indirect feedback Kalman filter structure, which is commonly used in aided navigation systems, for time-delayed measurement systems. Simulation and vehicle test results show effectiveness of a proposed algorithm.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.28 no.10
• /
• pp.1558-1565
• /
• 2004

It is important to determine supporting locations for structural stability when a structure is loaded with non-uniform load or supporting locations as well as the number of the supporting structures are restricted by the problem of space. Moreover, the supporting location optimization of complex structure in real world is frequently faced with discontinuous design space. Therefore, the traditional optimization methods based on derivative are not suitable Whereas, Genetic Algorithm (CA) based on stochastic search technique is a very robust and general method. The KSTAR in-vessel control coil installed in vacuum vessel is loaded with non- uniform electro-magnetic load and supporting locations are restricted by the problem of space. This paper shows the supporting location optimization for structural stability of the in-vessel control coil. Optimization has been performed by means of a developed program. It consists of a Finite Element Analysis interfaced with a Genetic Algorithm. In addition, this paper presents an algorithm to find an optimum solution in discontinuous space using continuous design variables.

• Journal of the Korean Society of Combustion
• /
• v.7 no.4
• /
• pp.29-35
• /
• 2002

[$CO_2$] is a well-known greenhouse gas, which is the major source of global warming. Many researchers have studied to reduce $CO_2$ emission in combustion processes. The central method of low $CO_2$ emission is Oxygen/CxHy combustion. Theoretically Oxygen/CxHy combustion only produces $CO_2\;and\;H_2O$ and allows convenient recovery of $CO_2$. The combustion characteristics, flame stability, composition in the flame zone and temperature profile were studied experimentally for various compositions of oxidant by substituting $CO_2\;for\;N_2$ with the constant $O_2$ concentration. Results showed that flame became unstable due to the high heat capacity, low transport rate and strong radiation effect of $CO_2$ in comparison with those of $N_2$. The reaction zone was quenched and broadened, as the ratio of $CO_2\;to\;N_2$ was increased. The emission of NOx in flue gas decreased due to the decreased temperature of the reaction zone. As the conversion ratio of $CO_2\;to\;N_2$ was increased, the emission of CO and the higher temperature zone increased due to decrease of reaction rate by the a quenching effect.

• Journal of Electrical Engineering and Technology
• /
• v.8 no.6
• /
• pp.1439-1450
• /
• 2013

This paper investigates a robust neuro-fuzzy control (NFC) method which can accurately follow the speed reference of an interior permanent magnet synchronous motor (IPMSM) in the existence of nonlinearities and system uncertainties. A neuro-fuzzy control term is proposed to estimate these nonlinear and uncertain factors, therefore, this difficulty is completely solved. To make the global stability analysis simple and systematic, the time derivative of the quadratic Lyapunov function is selected as the cost function to be minimized. Moreover, the design procedure of the online self-tuning algorithm is comparatively simplified to reduce a computational burden of the NFC. Next, a rotor angular acceleration is obtained through the disturbance observer. The proposed observer-based NFC strategy can achieve better control performance (i.e., less steady-state error, less sensitivity) than the feedback linearization control method even when there exist some uncertainties in the electrical and mechanical parameters. Finally, the validity of the proposed neuro-fuzzy speed controller is confirmed through simulation and experimental studies on a prototype IPMSM drive system with a TMS320F28335 DSP.

• Journal of the Korean Applied Science and Technology
• /
• v.30 no.3
• /
• pp.528-539
• /
• 2013

Biodiesel is one of the most important renewable energy, since it is one of the most important alternative and eco-friendly energy source compared to fossil energy, especially for diesel engineequipped vehicles. It is now coming up for preparation of biodiesel as the alternative that applies the hetrogeneous catalyst, super critical state and various methods used in order to reduce the stages of the processes be converted and separation stages started from oil and fat which are originated from animals and wastes, and those new methods bring eco-friendly as well, though some of those are stand on research step so far. It is necessary that nation provides the tax exemption program for the supplier and strengthen the research system for the farming crops relate to fat and oil. It can improve the development of biodiesel which sustains stability against oxidation and keeps good mobility over the low temperatures in the winter season by new additives and develops new processes to show good harmony with diesel engine.

• KSBB Journal
• /
• v.26 no.6
• /
• pp.491-504
• /
• 2011

This review article provides an overview of the evolution of diphtheria vaccine, its value and its future. Diphtheria is an infectious illness caused by diphtheria toxin produced by pathogenic strains of Corynebacterium diphtheriae. It is characterized by a sore throat with membrane formation due to local tissue necrosis, which can lead to fatal airway obstruction; neural and cardiac damage are other common complications. Diphtheria vaccine was first brought to market in the 1920s, following the discovery that diphtheria toxin can be detoxified using formalin. However, conventional formalin-inactivated toxoid vaccines have some fundamental limitations. Innovative technologies and approaches with the potential to overcome these limitations are discussed in this paper. These include genetic inactivation of diphtheria toxoid, innovative vaccine delivery systems, new adjuvants (both TLR-independent and TLR-dependent adjuvants), and heat- and freeze-stable agents, as well as novel platforms for producing improved conventional vaccine, DNA vaccine, transcutaneous (microneedle-mediated) vaccine, oral vaccine and edible vaccine expressed in transgenic plants. These innovations target improvements in vaccine quality (efficacy, safety, stability and consistency), ease of use and/or thermal stability. Their successful development and use should help to increase global diphtheria vaccine coverage.

• Proceedings of the KIEE Conference
• /
• 1999.07b
• /
• pp.528-530
• /
• 1999

This paper addresses the analysis and design of fuzzy control systems for a class of complex single input single output nonlinear systems. Firstly, the nonlinear system is represented by well-known Takagai-Sugeno (TS) fuzzy model and the global controller is constructed by compensating each linear model in the rule of TS fuzzy model. The design of conventional TS fuzzy-model-based controller usually is composed of two processes. One is to determine static state feedback gain of each local model and the other is to validate the stability of the designed fuzzy controller. In this paper, we propose an alternative of the design of TS fuzzy-model-based controller. The design scheme is based on the extension of conventional optimal control theory to the design of TS fuzzy-model-based controller. By using the proposed method the design and stability analysis of the TS fuzzy model-based controller is reduced to the problem of finding the solution of a set of algebraic Riccati equations. And we use the recently developed interior point method to find the solution of AREs, where AREs are recast as the LMI formulation. One simulation example is given to show the effectiveness and feasibility of the proposed fuzzy controller design method.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.29 no.12 s.243
• /
• pp.1352-1359
• /
• 2005

Unsteady simulations were performed to investigate the flame structure and the dynamic behavior of a premixed flame exposed to the wall heat loss. A 3-step global reaction mechanism was adopted in this study. Simulations were performed for two tube combustors with inner diameters($d_i$) of 1mm and 4mm. The material of tube combustor was assumed to be a Silicon Nitride($Si_{3}N_4$). The heat loss from the outer tube wall was controlled by adjusting the amount of convective and radiative heat loss. A conical premixed flame could be stabilized inside a tube of $d_i=4mm$. The flame stability inside a tube of $d_i=4mm$ combustor was not much sensitive to the amount of heat loss. In case of a tube of $d_i=1mm$, an oscillating flame was observed in very low heat loss condition and a flame could not be sustained in realistic heat loss condition.

• Journal of The Korean Society of Integrative Medicine
• /
• v.4 no.1
• /
• pp.13-20
• /
• 2016

Purpose : The purpose of this study was to compare the effect of exercise on the neck muscles activities between scapular stability and McKenzie stretch exercise in the forward head posture subjects. Method : After measuring cervical alignment using the Global Posture System, 20 volunteers with forward head posture posture were selected and divided into two groups. The experimental group A(n=15) and Experimental group B(n=15) participated in respectively and McKenzie neck stretching exercise, three times per week for 4 weeks. The scapular stabilization exercise program was comprised middle and lower trapezius strength exercises and the stretching exercise program was comprised levator scapulae and upper trapezius stretching exercise. The activities of the muscles of the posterior neck was then measured using electromyography. Result : After the intervention, there was significant difference of a electromyography activity changes between the pre-test and post-test in the experimental group. Conclusion : This study showed that both scapular stabilization and McKenzie neck stretching exercises are more effective for reducing neck muscles activities.

• The Journal of Asian Finance, Economics and Business
• /
• v.4 no.4
• /
• pp.51-60
• /
• 2017

India is the top recipient of workers' remittance flows; recent data indicate that the Remittances/GDP ratio has increased from 2.7% in 2000 to 3.36% in 2015. We apply a consumption behavior model, based on the "permanent income hypothesis", to estimate the consumption augmentation and the stability impact for the period of 1989-2014. The independent variables are: (i) real per capita income (exclusive of remittances) is the measure of "permanent income", (ii) remittances is the measure of "transitory income", and (iii) real interest rate as the indicator of consumers' ability for intertemporal consumption. The economic ramifications are important since current global risk factors could decrease flows in the future. The results indicate the significance of all three variables; there are: (i) evidence of significant consumption augmentation, (ii) consumption responds higher to remittances than to real income, the remittance elasticity is 0.571 and the income elasticity is 0.31, and (iii) evidence of pro-cyclical effect. The VAR model indicates some linkages and causality in the series that result in small response to the shocks. Policies to increase or stabilize remittance flows and to leverage remittances for economic development are important.