• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.9
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• pp.73-80
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• 2004

In this paper, we present the cell resequencing buffer to solve the cell sequence integrity problem of the Cyclic banyan network that is a high-performance fault-tolerant cell switch. By offering multiple paths between input ports and output ports, using the deflection self-routing, the Cyclic banyan switch offer high reliability, and it also solves congestion problem for the internal links of the switch. By the way, these multiple paths can be different lengths for each other. Therefore, the cells departing from an identical source port and arriving at an identical destination port can reach to the output port as the order that is different from the order arriving at input port. The proposed cell resequencing buffer is a hardware sliding window mechanism. to solve such cell sequence integrity problem. To calculate the size of sliding window that cause the prime cost of the presented device, we analyzed the distribution of the cell delay through the simulation analyses under traffic load that have a nonuniform address distribution that express tile Property of traffic of the Internet. Through these analyses, we found out that we can make a cell resequencing buffer by which the cell sequence integrity is to be secured, by using a, few of ordinary memory and control logic. The cell resequencing buffer presented in this paper can be used for other multiple paths switching networks.

• Journal of Biomedical Engineering Research
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• v.25 no.6
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• pp.447-453
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• 2004

In the case of a capsule that can acquire and transmit images from the intestines, the size of the module and the battery capacity in the capsule are subject to restriction. The capsule must be swallowable and the battery must maintain the stable power during the capsule travels in the gastrointestinal tract. Therefore, it is important to control the endoscope using bi-directional wireless communication. In this study, encoder and decoder CPLD modules for bi-directional capsule endoscopes were designed and implemented. The designed controller for capsule endoscope can transmit the images of GI-track from inside to outside of the body and the capsules can be controlled by external controller simultaneously. The designed and implemented controller was verified by an in-vivo animal experiments. From these experiments, it was verified that the CPLD module for bi-directional capsule endoscope satisfied the design specifications.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.3
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• pp.325-336
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• 2020

Nonlinear Invariant Attack is an attack that should be considered when constructing lightweight block ciphers with relatively simple key schedule. A shortcut to prove a block cipher's resistance against nonlinear invariant attack is checking the smallest dimension of linear layer-invariant linear subspace which contains all known differences between round keys is equal to the block size. In this paper, we presents the following results. We identify the structure and number of optimal bit-permutations which require only one known difference between round keys for a designer to show that the corresponding block cipher is resistant against nonlinear invariant attack. Moreover, we show that PRESENT-like block ciphers need at least two known differences between round keys by checking all PRESENT-like bit-permutations. Additionally, we verify that the variants of PRESENT-like bit-permutations requiring the only two known differences between round keys do not conflict with the resistance against differential attack by comparing the best differential trails. Finally, through the distribution of the invariant factors of all bit-permutations that maintain BOGI logic with GIFT S-box, GIFT-variant block ciphers require at least 8 known differences between round keys for the resistance.

• Journal of Advanced Navigation Technology
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• v.25 no.1
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• pp.68-77
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• 2021

In this paper, a GPS/MEMS IMU integrated navigation receiver module capable of operating in a high dynamic environment is designed and fabricated, and the results is confirmed. The designed module is composed of RF receiver unit, inertial measurement unit, signal processing unit, correlator, and navigation S/W. The RF receiver performs the functions of low noise amplification, frequency conversion, filtering, and automatic gain control. The inertial measurement unit collects measurement data from a MEMS class IMU applied with a 3-axis gyroscope, accelerometer, and geomagnetic sensor. In addition, it provides an interface to transmit to the navigation S/W. The signal processing unit and the correlator is implemented with FPGA logic to perform filtering and corrrelation value calculation. Navigation S/W is implemented using the internal CPU of the FPGA. The size of the manufactured module is 95.0×85.0×.12.5mm, the weight is 110g, and the navigation accuracy performance within the specification is confirmed in an environment of 1200m/s and acceleration of 10g.

• Journal of IKEEE
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• v.26 no.3
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• pp.422-429
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• 2022

A light sensor chip requires a small capacity eFuse (electrical fuse) OTP (One-Time Programmable) memory IP (Intellectual Property) to trim analog circuits or set initial values of digital registers. In this paper, 128-bit eFuse OTP IP is designed using only 3.3V MV (Medium Voltage) devices without using 1.8V LV (Low-Voltage) logic devices. The eFuse OTP IP designed with 3.3V single MOS devices can reduce a total process cost of three masks which are the gate oxide mask of a 1.8V LV device and the LDD implant masks of NMOS and PMOS. And since the 1.8V voltage regulator circuit is not required, the size of the illuminance sensor chip can be reduced. In addition, in order to reduce the number of package pins of the illumination sensor chip, the VPGM voltage, which is a program voltage, is applied through the VPGM pad during wafer test, and the VDD voltage is applied through the PMOS power switching circuit after packaging, so that the number of package pins can be reduced.

• Tunnel and Underground Space
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• v.33 no.1
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• pp.57-69
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• 2023

In this study, we simulated induced seismicity in the Groningen natural gas reservoir using 2D hydro-mechanical coupled discrete element modelling (DEM). The code used is PFC2D (Particle Flow Code 2D), a commercial software developed by Itasca, and in order to apply to this study we further developed 1)initialization of inhomogeneous reservoir pressure distribution, 2)a non-linear pressure-time history boundary condition, 3)local stress field monitoring logic. We generated a 2D reservoir model with a size of 40 × 50 km² and a complex fault system, and simulated years of pressure depletion with a time range between 1960 and 2020. We simulated fault system failure induced by pressure depletion and reproduced the spatiotemporal distribution of induced seismicity and assessed its failure mechanism. Also, we estimated the ground subsidence distribution and confirmed its similarity to the field measurements in the Groningen region. Through this study, we confirm the feasibility of the presented 2D hydro-mechanical coupled DEM in simulating the deformation of a complex fault system by hydro-mechanical coupled processes.

• The Korean Journal of Nuclear Medicine
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• v.32 no.4
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• pp.365-373
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• 1998

Purpose: The conventional gamma camera is not ideal for scintimammography because of its large detector size (${\sim}500mm$ in width) causing high cost and low image quality. We are developing a small gamma camera dedicated for breast imaging. Materials and Methods: The small gamma camera system consists of a NaI (T1) crystal ($60 mm{\times}60 mm{\times}6 mm$) coupled with a Hamamatsu R3941 Position Sensitive Photomultiplier Tube (PSPMT), a resister chain circuit, preamplifiers, nuclear instrument modules, an analog to digital converter and a personal computer for control and display. The PSPMT was read out using a standard resistive charge division which multiplexes the 34 cross wire anode channels into 4 signals ($X^+,\;X^-,\;Y^+,\;Y^-$). Those signals were individually amplified by four preamplifiers and then, shaped and amplified by amplifiers. The signals were discriminated ana digitized via triggering signal and used to localize the position of an event by applying the Anger logic. Results: The intrinsic sensitivity of the system was approximately 8,000 counts/sec/${\mu}Ci$. High quality flood and hole mask images were obtained. Breast phantom containing $2{\sim}7 mm$ diameter spheres was successfully imaged with a parallel hole collimator The image displayed accurate size and activity distribution over the imaging field of view Conclusion: We have succesfully developed a small gamma camera using NaI(T1)-PSPMT and nuclear Instrument modules. The small gamma camera developed in this study might improve the diagnostic accuracy of scintimammography by optimally imaging the breast.

• The Korean Journal of Nuclear Medicine
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• v.34 no.1
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• pp.82-93
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• 2000

Purpose: We characterized the signals obtained from the components of a small gamma camera using Nal(Tl)-position sensitive photomultiplier tube (PSPMT) and optimized the parameters employed in the modules of the system. Materials and Methods: The small gamma camera system consists of a Nal(Tl) crystal ($60{\times}60{\times}6mm^3$) coupled with a Hamamatsu R3941 PSPMT, a resister chain circuit, preamplifiers, nuclear instrument modules (NIMs), an analog to digital converter and a personal computer for control and display. The PSPMT was read out using a resistive charge division circuit which multiplexes the 34 cross wire anode channels into 4 signals (X+, X-, Y+, Y -). Those signals were individually amplified by four preamplifiers and then, shaped and amplified by amplifiers. The signals were discriminated and digitized via triggering signal and used to localize the position of an event by applying the Anger logic. The gamma camera control and image display was performed by a program implemented using a graphic software. Results: The characteristics of signal and the parameters employed in each module of the system were presented. The intrinsic sensitivity of the system was approximately $8{\times}10^3$ counts/sec/${\mu}Ci$. The intrinsic energy resolution of the system was 18% FWHM at 140 keV. The spatial resolution obtained using a line-slit mask and $^{99m}Tc$ point source were, respectively, 2.2 and 2.3 mm FWHM in X and Y directions. Breast phantom containing $2{\sim}7mm$ diameter spheres was successfully imaged with a parallel hole collimator. The image displayed accurate size and activity distribution over the imaging field of view Conclusion: We proposed a simple method for development of a small gamma camera and presented the characteristics of the signals from the system and the optimized parameters used in the modules of the small gamma camera.