• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.219-224
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• 2011

Recently increasing importance of information security, personal security is researched. Among them, biometrics research is very good at recognition and security particularly in terms of iris recognition. Recent hospital physicians and employees for access control is emphasized. But most of them, easy-employee card access control systems are used. It has difficulties of iris recognition on the issue of accurate iris recognition algorithm to eliminate noise and inaccuracy of pretreatment methods for recognition from existing research. Therefore, this paper complements existing encryption methods to the disadvantages of biometric iris recognition using high-access records in the hospital management system is applied. In addition to conventional pretreatment process to increase recognition eyebrows when mask line component added to the extraction mask, the correct preparation method, and accordingly proposed to improve the recognition of records management systems offer access to the hospital.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.2
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• pp.145-151
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• 2012

The pulsimeter is a representative device in the oriental medicine, which can analysis a risk factor in a cardiovascular diseases. However, most of the previous methods have the limit by the contacted sate of the brachial pulse and sensor in the measuring time, the inaccuracy of detected pulse, and the difficulty of pulse analysis. Accordingly, we propose the moving pulse image analysis based pulsimeter that can acquire a pulse of patient in real time by analyzing a moving image. then this video is shot the state change of the T.S. occurred by a pulse in capillary. In order to evaluate the performance of the our pulsimeter, we measured a respective detecting-rate about the essential 5 feature-points in the pulse analysis from the detected original pulse. As a result, the proposed method is very successful.

• Smart Structures and Systems
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• v.25 no.2
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• pp.155-167
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• 2020

This paper demonstrates a real-time hybrid substructuring (RTHS) shake table test to evaluate the seismic performance of a base isolated building. Since RTHS involves a feedback loop in the test implementation, the frequency dependent magnitude and inherent time delay of the actuator dynamics can introduce inaccuracy and instability. The paper presents a robust stability and performance analysis method for the RTHS test. The robust stability method involves casting the actuator dynamics as a multiplicative uncertainty and applying the small gain theorem to derive the sufficient conditions for robust stability and performance. The attractive feature of this robust stability and performance analysis method is that it accommodates linearized modeled or measured frequency response functions for both the physical substructure and actuator dynamics. Significant experimental research has been conducted on base isolators and dampers toward developing high fidelity numerical models. Shake table testing, where the building superstructure is tested while the isolation layer is numerically modeled, can allow for a range of isolation strategies to be examined for a single shake table experiment. Further, recent concerns in base isolation for long period, long duration earthquakes necessitate adding damping at the isolation layer, which can allow higher frequency energy to be transmitted into the superstructure and can result in damage to structural and nonstructural components that can be difficult to numerically model and accurately predict. As such, physical testing of the superstructure while numerically modeling the isolation layer may be desired. The RTHS approach has been previously proposed for base isolated buildings, however, to date it has not been conducted on a base isolated structure isolated at the ground level and where the isolation layer itself is numerically simulated. This configuration provides multiple challenges in the RTHS stability associated with higher physical substructure frequencies and a low numerical to physical mass ratio. This paper demonstrates a base isolated RTHS test and the robust stability and performance analysis necessary to ensure the stability and accuracy. The tests consist of a scaled idealized 4-story superstructure building model placed directly onto a shake table and the isolation layer simulated in MATLAB/Simulink using a dSpace real-time controller.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.3
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• pp.230-237
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• 2020

In order to design a diesel engine system and predict its performance, it is necessary to analyze the gas flow of the intake and exhaust system. A gas flow analysis in three-dimensional (3D) format needs a high-resolution workstation and enormous time for analysis. Therefore, the method of characteristics (MOC) was used for a gas flow analysis with a fast calculation time and a low-resolution workstation. An experiment was conducted on a single cylinder diesel engine to measure pressure in cylinder, intake pipe and exhaust pipe. The one-dimensional (1D) gas flow was analyzed under the same conditions as the experiment. The engine speed, valve timing and compression ratio were the same conditions and the intake pressure was inputted as the experimental results. Bent pipe such as an exhaust port that cannot be realized in 1D was omitted. As results of validation, the cylinder pressure showed accuracy, but the exhaust pipe pressure exhibited inaccuracy. This is considered as an error caused by the failure to implement a bent pipe such as an exhaust port. When analyzed in 3D, calculation time required 61 hours more based on a model of this study. In the future, we intend to implement a bent pipe that cannot be realized in 1D using 3D and prepare a method to supplement reliability by using 1D-3D coupling.

• Journal of the Korea Computer Graphics Society
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• v.2 no.1
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• pp.7-14
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• 1996

A particle system is defined as a collection of primitive particles that together represent irregular and ever-changing objects such as smoke, clouds, waterfalls, and explosions. A particle system can be a powerful tool for modeling a deformable object's motion and change of form since it has dynamic properties with time. As an object becomes more complicated and shows more chaotic behavior, however, we need much more parameters for describing its characteristics completely. Consequently, the conventional particle system leads to difficulty in managing all of the parameters properly since one parameter can affect the others. Moreover, motion equations for representing particles' behavior are usually approximated to gain speed-ups. The inevitable errors in calculating the equations can cause an unexpected outcome. In this paper, we present a new approach of applying fuzzy contol to mage particles' motion and attributes changes over time. We also give an implementation result of a fuzzy particle system to show the feasibility of the proposed method. Applications of the system to explosions, nebulae, volcanos, and grass are presented.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.1
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• pp.38-45
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• 2017

Attacking of computer and network is increasing as information processing technology heavily depends on computer and network. To prevent the attack of system and network, host and network based intrusion detection system has developed. But previous rule based system has a lot of difficulties. For this reason demand for developing a intrusion detection system which detects and cope with the attack of system and network resource in real time. In this paper we develop a real time intrusion detection system which is combination of APEX and LS-SVM classifier. Proposed system is for nonlinear data and guarantees convergence. While real time processing system has its advantages, such as memory efficiency and allowing a new training data, it also has its disadvantages of inaccuracy compared to batch way. Therefore proposed real time intrusion detection system shows similar performance in accuracy compared to batch way intrusion detection system, it can be deployed on a commercial scale.

• Journal of the Optical Society of Korea
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• v.19 no.4
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• pp.415-420
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• 2015

A novel method to measure the scale factor for the all-optical atomic spin inertial measurement device (ASIMD) is demonstrated in this paper. The method can realize the calibration of the scale factor by a self-consistent method with small errors in the quiescent state. At first, the matured IMU (inertial measurement unit) device was fixed on an optical platform together with the ASIMD, and it has been used to calibrate the scale factor for the ASIMD. The results show that there were some errors causing the inaccuracy of the experiment. By the comparative analysis of theory and experiment, the ASIMD was unable to keep pace with the IMU. Considering the characteristics of the ASIMD, the mismatch between the driven frequency of the optical platform and the bandwidth of the ASIMD was the major reason. An all-optical atomic spin magnetometer was set up at first. The sensitivity of the magnetometer is ultra-high, and it can be used to detect the magnetization of spin-polarized noble gas. The gyromagnetic ratio of the noble gas is a physical constant, and it has already been measured accurately. So a novel calibration method for scale factor based on the gyromagnetic ratio has been presented. The relevant theoretical analysis and experiments have been implemented. The results showed that the scale factor of the device was $7.272V/^{\circ}/s$ by multi-group experiments with the maximum error value 0.49%.

• Horticultural Science & Technology
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• v.16 no.1
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• pp.25-26
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• 1998

Nutrient supplying by a metering pump often produces the inaccuracy in the rate of inflow than expected. In this study, we developed the transpiration estimation system using the metering pump to measure the continuous supplying rate as well as to estimate the accurate transpiration rate. The system showed the stable characteristics by eliminating the fluctuations in the head loss of nutrient tank. The direct proportionality between the supplying time and the supplied nutrient solution was obtained. The exact correlation between the integrated solar radiation and the transpiration rate using the system was calculated, and correlation coefficients between the two factors were 0.98 in the NFT system and 0.92 in the aggregate system. This results suggest that the integrated solar radiation was an important factor to directly decide the supplying volume of nutrient solution in soilless culture system. The deveolped system using the metering pump in the study was able to control the supply of the nutrient solution to the crops adjusting to the variation of solar radiation.

• Journal of The Korean Astronomical Society
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• v.38 no.2
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• pp.59-66
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• 2005

A new ion transport code for planetary ionospheric studies has been developed with consideration of velocity differences among ion species involving ion-ion collision. Most of previous planetary ionosphere models assumed that ions diffuse through non-moving ion and neutral background in order to consolidate continuity and momentum equations for ions into a simple set of diffusion equations. The simplification may result in unreliable density profiles of ions at high altitudes where ion velocities are fast and their velocity differences are significant enough to cause inaccuracy when computing ion-ion collision. A new code solves explicitly one-dimensional continuity and momentum equations for ion densities and velocities by utilizing divided Jacobian matrices in matrix inversion necessary to the Newton iteration procedure. The code has been applied to Martian nightside ionosphere models, as an example computation. The computed density profiles of $O^+,\;OH^+$, and $HCO^+$ differ by more than a factor of 2 at altitudes higher than 200 km from a simple diffusion model, whereas the density profile of the dominant ion, $O_2^+$, changes little. Especially, the density profile of $HCO^+$ is reduced by a factor of about 10 and its peak altitude is lowered by about 40 km relative to a simple diffusion model in which $HCO^+$ ions are assumed to diffuse through non-moving ion background, $O_2^+$. The computed effects of the new code on the Martian nightside models are explained readily in terms of ion velocities that were solved together with ion densities, which were not available from diffusion models. The new code should thus be expected as a significantly improved tool for planetary ionosphere modelling.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.1
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• pp.125-133
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• 2010

A versatile micro-robotic platform for micro/nano scale assembly has been demanded in a variety of application areas such as micro-biology and nanotechnology. In the near future, a flexible and compact platform could be effectively used in a scanning electron microscope chamber. We are developing a platform that consists of miniature mobile robots and a compact positioning stage with multi degree-of-freedom. This paper presents the design and the implementation of a low-cost and compact multi degree of freedom position sensor that is capable of measuring absolute translational and rotational displacement. The proposed sensor is implemented by using a CMOS type image sensor and a target with specific hole patterns. Experimental design based on statistics was applied to finding optimal design of the target. Efficient algorithms for image processing and absolute position decoding are discussed. Simple calibration to eliminate the influence of inaccuracy of the fabricated target on the measuring performance also presented. The developed sensor was characterized by using a laser interferometer. It can be concluded that the sensor system has submicron resolution and accuracy of ${\pm}4{\mu}m$ over full travel range. The proposed vision-based sensor is cost-effective and used as a compact feedback device for implementation of a micro robotic platform.