• Journal of Korea Water Resources Association
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• v.44 no.12
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• pp.955-965
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• 2011

The flow characteristics of rectangular and 1 : 1 and 1 : 2 trapezoidal weirs were investigated through hydraulic experiments in order calculate the exact overflow discharge of the broad-crested side weir. The flow was found to be most stable in trapezoidal shapes with the lowest incline. The 1 : 1 and 1 : 2 trapezoidal weirs had 5.67% and 8.57% increases, respectively, compared to the rectangular weir in terms of overflow amount, which suggests that they are more effective in preventing flood. An integrated discharge coefficient equation taking into account the discharge coefficient equation and shapes was proposed through a multiple linear regression analysis with an addition of a new parameter for the side wear, $L/L_H$, to the conventional discharge coefficient equation. Also, the applicability of the newly proposed discharge coefficient equation was reviewed by comparing the measured and calculated overflow amounts based on the experimental data of preceding researches and existing researchers and the research data of this study.

• Journal of KIISE:Software and Applications
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• v.28 no.11
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• pp.864-873
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• 2001

In this paper, a new approach to building a registration authority for issuing PKI-based certificates is presented to make the process of identifying an individual more secure and reliable by utilizing human iris recognition technology. The tasks of the proposed system associated with the manipulation of irises except for the general functions of registration authorities can be categorized into three modules, the acquisition of iris images, the registration of iris information, and the verification of users by means of iris patterns. The information among the three modules is safely exchanged through encryption and decryption with a symmetric cryptographic method. As a feature extraction method for a given iris image, a wavelet transform is applied to represent a feature vector with a small dimension of information obtained by subsampling an image corresponding to lower frequency bands successively without loss of information. Through the experiments on human iris recognition technology we proposed and applied to the registration authority, the potential of biometric technology in various applications is confirmed.

• Journal of Broadcast Engineering
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• v.8 no.1
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• pp.19-29
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• 2003

The demand for high-resolution images is gradually increasing, whereas many imaging systems yield aliased and undersampled images during image acquisition. In this paper, we propose a high-resolution image reconstruction algorithm considering inaccurate subpixel registration. A regularized Iterative reconstruction algorithm is adopted to overcome the ill-posedness problem resulting from inaccurate subpixel registration. In particular, we use multichannel image reconstruction algorithms suitable for application with multiframe environments. Since the registration error in each low-resolution has a different pattern, the regularization parameters are determined adaptively for each channel. We propose a methods for estimating the regularization parameter automatically. The preposed algorithm are robust against the registration error noise. and they do not require any prior information about the original image or the registration error process. Experimental results indicate that the proposed algorithms outperform conventional approaches in terms of both objective measurements and visual evaluation.

• Journal of Digital Convergence
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• v.18 no.9
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• pp.199-210
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• 2020

The objective of this study was to identify generational difference of work value and job engagement. Total 256 nurses participated in Korea. Analysis of variance(ANOVA) was conducted to investigate the generational differences of work value and job engagement and factors of work values influencing to job engagement was identified by multiple regression analysis. Nurses considered financial benefits, job security, and work environment as the most important thing and autonomy, possibilities of promotion, and contribution to society were considered less important in their work life. Y and Z-generation nurses respected more to interests at work and time availability for private life than X-generation in work life.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.8
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• pp.75-84
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• 2004

In this paper, we proposed an efficient hardware architecture of line-based lifting algorithm for Motion JPEG2000. We proposed a new architecture of a lifting-based filtering cell which has an optimized and simplified structure. It was implemented in a hardware accommodating both (9,7) and (5,4) filter. Since the output rate is linearly proportional to the input rate, one can obtain the high throughput through parallel operation simply by adding the hardware units. It was implemented into both of ASIC and FPGA The 0.35${\mu}{\textrm}{m}$ CMOS library from Samsung was used for ASIC and Altera was the target for FRGA. In ASIC, the proposed architecture used 41,592 gates for the lifting arithmetic and 128 Kbit memory. For FPGA it used 6,520 LEs(Logic Elements) and 128 ESBs(Embedded System Blocks). The implementations were stably operated in the clock frequency of 128MHz and 52MHz, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.8B
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• pp.954-961
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• 2011

To apply Wi-Fi technique to the Broadcast field, we have to study features of IEEE 802.11 Broadcast packet. IEEE 802.11 Broadcast technique cannot guarantee successful packet delivery than IEEE 802.11 Unicast. A promising solution to this problem is the use of FEC(Forward Error Correction) mechanisms. However, the adjustment of the FEC redundancy rate is not a trivial issue due to the dynamic wireless environment. In order to explore the above issues we conducted an experimental study of the packet loss behavior of the IEEE 802.11g protocol. In order to study, we implemented a broadcast test bed. Based on the experimental results, we provide guidelines on wireless lan parameters(packet size, transmission rate(11g), background traffic). From this experimental study, we provide FEC redundancy rate.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.9
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• pp.2044-2055
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• 2015

Financial information systems play such a pivotal role in the financial institution services that are provided for a large customers on the basis of various information including the personal information. As for the personal information collected during the transactions in the financial information systems, huge efforts and investment have been made to protect previously them from being inappropriately misused or illegally used if they could be released. Unfortunately, the frequent accidents on the leakage of sensitive personal information have occurred recently not only by external service users but even by internal system users. Therefore, the aim of this study is to suggest a model of advanced two-channel authentication for internal users in order to increase the stability of financial information systems with enhanced security.

• Journal of Convergence for Information Technology
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• v.7 no.2
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• pp.59-65
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• 2017

In order to realize the operation of the creative modular toy, it is required to record the motion and to read and repeat the motion. At this time, a control potentiometer is used to read the absolute angle of rotation of the toy motion output shaft. However, the unstable part of the sensing area of the potentiometer is present in a certain region, which may lead to instability of the motor control. In this paper, we propose an algorithm to find the absolute angle of one rotation by reading two stable potentiometers on one axis and reading each stable region. We also describe the correction algorithm that is needed to perform multiple rotations. The proposed method is applied to Topobo modular toys to record the operation and perform iterative operation. In addition, multi-turn operation is recorded and operated to suggest the usefulness of the proposed method. In the future, we will expand the functions of recording and playback through various actions.

• Journal of Advanced Navigation Technology
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• v.23 no.3
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• pp.228-236
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• 2019

Recently, multi-sensor integration techniques have been actively studied to obtain reliable and accurate navigation solution in GPS (Global Positioning System)-denied harsh environments such as urban canyons, tunnels, and underground roads. In this paper, we propose a low-cost ultrasonic-speedometer utilizing the characteristics of the ultrasonic propagation. An efficient integrated INS (inertial navigation system)/ultrasonic-speedometer navigation system is also proposed to improve the accuracy of positioning in GPS-denied environments. To evaluate the proposed system, car experiments with field-collected measurements were performed. By the experiment results, it was confirmed that the proposed INS/ultrasonic-speedometer system bounds the positioning error growth effectively even though GPS signal is blocked more than 10 seconds and a low-cost MEMS IMU (micro electro mechanical systems inertial measurement unit) is utilized.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.4
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• pp.119-125
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• 2022

The power supply for the anti-aircraft radar homing sensor should allow the system to receive power quickly and stably without the influence of noise. For this purpose, DC-DC converters are widely used for reliable power conversion. Also, switching of DC-DC converters Frequency noise should not cause false alarms and ghosts that may affect the detection and tracking performance of the system, and it should have a check function that can monitor power in real time while the homing sensor is operating. In order to apply to anti-aircraft radar homing sensor, we developed a multi-output switching power supply with maximum output 𐩒𐩒𐩒 W, efficiency 80% or more (@100% load), output power by receiving 28VDC input, and power supply to achieve more than 80% efficiency. A DC-DC converter was applied to this large output, and the multi-output flyback method was applied to the rest of the low-power output.