• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.4
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• pp.407-415
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• 2011

The stability condition and wideband characteristics of 3D ID-FDTD algorithm which has low dispersion error with isotropic dispersion are presented in this paper. 3D ID-FDTD method was proposed to improve the defect of the Yee FDTD such as the anisotropy and large dispersion error. The published paper calculated the stability condition of 3D ID-FDTD algorithm by using numerical method, however, it is thought that the examples were not sufficient to verify the stability condition. Thus, in this paper, various simulations are included in order to hold reliability under the conditions that the plane wave propagation is assumed with a single frequency and a wideband frequency. Also, the 3D ID-FDTD algorithm is compared to those that have the similar FDTD algorithm with ID-FDTD such as Forgy's method and non-standard FDTD method in a wideband. Finally, the radar cross section(RCS) for the large sphere with high dielectric constant is calculated.

• The Journal of the Acoustical Society of Korea
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• v.32 no.2
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• pp.138-146
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• 2013

Passive sonars employ DEMON (Detection of Envelope Modulation on Noise) processing to extract propeller information from the radiated noise of underwater targets. Conventional DEMON processing improves SNR(Signal to Noise Ratio) characteristic by Welch method. The conventional Welch method overlaps several different time domain DEMON outputs to reduce the variance. However, the conventional methods have high computational complexity to get high SNR with correlated acoustic signals. In this paper, we propose new DEMON processing method that divides acoustic signal into several frequency bands before DEMON processing and averages each DEMON outputs. Therefore, the proposed method gathers independent acoustic signal faster than conventional method with low computational complexity. We prove the performance of the proposed method with mathematical analysis and computer simulations.

• Korean Journal of Optics and Photonics
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• v.17 no.6
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• pp.544-547
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• 2006

A time-domain modeling approach is used to study characteristics of a widely tunable coupled-ring reflector (CRR) laser diode(LD). The CRR consists of a bus waveguide and two coupled ring resonators coupled to the bus without resorting to distributed Bragg grating structure. The tuning range can be a few tens of nanometers with a side mode suppression ratio exceeding 35dB through the adjustment of currents into the phase control sections in the rings. The CRR laser diode has long effective cavity length compared to conventional laser diodes. Accordingly, a broad additional resonance peak in the amplitude modulation characteristics is observed between 20 to 30 GHz, implying the extension of amplitude modulation bandwidth.

• Journal of Digital Convergence
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• v.18 no.8
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• pp.231-242
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• 2020

The thesis presents a system that continuously collects the human body's physiological vital information at rest with sensors and ICT information technology and predicts diabetes using the collected information. it shows the artificial neural network machine learning method and essential basic variable values. The study method analyzed the correlation between heart rate measurements of BCG and ECG sensors in 20 DM- and 15 DM+ subjects. Artificial Neural Network (ANN) machine learning program was used to predictability of diabetes. The input variables are time domain information of HRV, heart rate, heart rate variability, respiration rate, stroke volume, minimum blood pressure, highest blood pressure, age, and sex. ANN machine learning prediction accuracy is 99.53%. Thesis needs continuous research such as diabetic prediction model by BMI information, predicting cardiac dysfunction, and sleep disorder analysis model using ANN machine learning.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.1
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• pp.67-74
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• 1998

The primary cause of air pollution by vehicles is imperfect combustion of fuel. One of the most usual causes of this imperfect combustion is the misfire in IC engins. The U.S. EPA(Environment Protection Agency) and the CARB(California air Resources Board) have imposed regulations for the detection of misfiring in automotive engines. The OBD-II regulations require that misfire should be monitored by the engine diagnostic system, and that the goal of OBD-II is to alert the driver to the presence of a malfunction of the emission control system. Several solutions to the misfire detection problem have been proposed for the detection of misfires. However, the performance of these methods in the presence of misfire is not altogether clear. This paper presents a precise method and system for internal combustion engine misfire. Present invention based upon measurements of engine roughness as derived from crankshaft angular velocity measurements with special signal processing method. Crankshaft angular velocity signals are processed by WDPT, so that the more reliable misfire detection than the time domain analysis. Experimental work confirms that it is possible to apply the WDFT for the detection of misfires in no-load idle and road testing.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.12
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• pp.1112-1115
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• 2016

Global Positioning System(GPS) is a useful system used in both civilian and military applications. However, the signal of GPS is susceptible to jamming attacks due to low receive sensitivity, since the signals come from the satellite located at over 20,000 km above the earth. In this paper, we have conducted a preceding research on a non-Foster matching circuit that efficiently matches an electrically ultra-small GPS antenna. Electrically Small Antennas(ESAs) are inefficient radiators and are difficult to match in wideband due to extremely high quality factor. In order to match small GPS antenna in wideband, a non-Foster matching circuit for a small GPS antenna was designed. A negative impedance converter circuit consisting of Linvill's cross-coupled pair transistors was fabricated and its stability was verified by the time-domain stability analysis. In addition, anechoic chamber measurements show that the non-Foster matching circuit for small GPS antenna can lead bore-sight gain improvement by more than 17 dB.

• Journal of Navigation and Port Research
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• v.42 no.2
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• pp.127-136
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• 2018

The motion response of floating structures is of significant concern in marine engineering. Floating structures can be disturbed by waves, winds, and currents that create undesirable motions of the vessel, therefore causing challenges to its operation. For a floating structure, mooring lines are provided in order to maintain its position; these should also produce a restoring force when the vessel is displaced. Therefore, it is important to investigate the tension of mooring lines and the motion responses of a twin barge when moored to guarantee the safety of the barge during its operation. It is essential to precisely identify the characteristics of the motion responses of a moored barge under different loading conditions. In this study, the motion responses of a moored twin barge were measured in regular waves of seven different wave directions. The experiment was performed with regular waves with different wavelengths and wave directions in order to estimate the twin-barge motions and the tension of the mooring line. In addition, the motion components of roll, pitch, and heave are completely free. In contrast, the surge, sway, and yaw components are fixed. In the succeeding step, a time-domain analysis is carried out in order to obtain the responses of the structure when moored. As a result, the Response Amplitude Operator (RAO) motion value was estimated for different wave directions. The results of the experiment show that the motion components of the twin barge have a significant effect on the tension of the mooring lines.

• Journal of the Korean Dietetic Association
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• v.19 no.4
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• pp.317-342
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• 2013

The purpose of this study was to evaluate the current state of foodservice and clinical nutrition management in a hospital-based nutrition department. Nutritional guidelines and survey reports of hospital evaluation programs from 2004 to 2009 were analyzed. In total, 275 hospitals in the first period and 288 hospitals in the second period were evaluated. The division of knife and chopping board use decreased from 97.2% in 2005 to 89.7% in 2008, the maintenance of a proper freezer temperature (below $-18^{\circ}C$) increased from 82.1% in 2004 to 97.7% in 2007 (88.9% to 97.4% from large hospitals and 69.8% to 86.5% from small/medium hospitals in 2005 and 2008, respectively). In tube-feeding management, the performance rate of material cold storage and the offer rate of tube-feeding were 65.9% and 94.2% in 2007, respectively. The cold storage of material, proper use within 24 hours after opening or production, and the use of an appropriate label were 47.3%, 71.2% and 67.2% in 2009, respectively. The rate of a management system for undernourished patients was 86.0% in 2007 (56.4% for large hospitals, 18.9% for small/medium hospitals) and 14.3% in 2009. In standards of nutrition support management, the performance rates of constructing a nutrition support team, the nutrition support team activity, and organizing multidisciplinary team were 66.7%, 43.6%, and 64.1% respectively, in 2004. For large hospitals, those rates were 61.1%, 36.1%, and 58.3%, in 2005, 93.0%, 62.8%, and 91.9% in 2007, and 69.2%, 43.6%, and 69.2% in 2008, respectively. The results of this study suggest standards on sanitary foodservice preparation, production, and tube-feeding production need to correspond with HACCP regulations for small/meidium hospitals in standards of a healthcare accreditation system. It will be necessary to understand the operating conditions of nutrition departments in convalescent hospitals, psychiatric hospitals, and geriatrics hospitals. As the application of accreditation is required from 2013, standards will need to be improved and continuously updated for healthcare accreditation.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.9
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• pp.19-27
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• 2002

Characteristics of interconnect lines considering underlayer geometries of a silicon substrate and crossing metal lines are experimentally analyzed through elaborately devised patterns. In this work, test patterns for transmission lines having several kinds of underlayer geometries were devised, and the signal characteristics and responses are measured by S-parameter and time domain reflection meter (TDR). The patterns were designed and fabricated with a deep-submicron CMOS DRAM technology having 1 Tungsten and 2 Aluminum metals. From the analysis of measured results on the patterns, it is founded that the effects of underlayter line structures on line parameters (especially line capacitance and resistance) and signal distortions occurred from them cannot be negligible. The results provide useful and insightful understanding in the skew balance of package leads and global signal lines such as high-speed clock and data lines.

• International Journal of Industrial Entomology and Biomaterials
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• v.23 no.2
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• pp.223-229
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• 2011

Cyclophilins are originally identified as cytosolic binding protein of the immunosuppressive drug cyclosporine A. They have an activity of peptidyl prolyl cis/trans-isomerases (PPIase), which may play important roles in protein folding, trafficking, assembly and cell signaling. In this study, we report the cloning and characterization of a Bombyx mori cyclophilin A (bCypA) cDNA. The full-length cDNA of bCypA consist of 947 nucleotides with a polyadenylation signal sequence AATAAA and contain an open reading frame of 498 nucleotides encoding a polypeptide of 166 amino acids. The deduced amino acid sequence of bCypA shares a central peptidyl prolyl cis/trans-isomerase and a cyclosporin-A-binding domain with other cyclophilin sequences. Relative quantification real-time (RT) PCR analysis shows that mRNA transcripts of bCypA are detected in all the investigated tissues and highest expression level in the skin of 3-day-old 5 instar larva. Also, bCypA had PPIase activity on the proline-containing peptides. Accordingly, we suggest that bCypA is a new member of the cyclophilin A (CyPA) family and will be useful for quality control of bioactivity recombinant proteins with proline-containing peptides.