• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.5
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• pp.195-201
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• 2013

The government has invested much budget for 5years to do the Smart-education and operate digital textbook services since 2011. The private enterprises also decided to focus on constructing Smart learning system by investing much budget. If these systems are constructed nationwide and therefore can access to cyber university by using smart devices, we can reduce the information gap and study online lectures to get a grade whenever, whoever and wherever we want to. However, these convenient systems can cause serious problems like falsifying grades by hacking if security systems are weak. In this paper, we formulated cyber university which is secured in terms of security. For this, we simulated the smart-learning system which strengthened the security, considering code algorithm and encryption technique.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.5
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• pp.333-340
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• 2003

Doppler processing is the heart of pulsed Doppler radar. It gives a clutter elimination and coherent integration. With the improvement of digital signal processors (DPSs), the implementation using them is more widely used in radar systems. Generally, so as for Doppler processor to process the input data in real time, a parallel processing concept using multiple DSPs should be used. This paper implements a programmable Doppler processor, which consists of MTI filter, DFB and square-law detector, using 8 ADSP21060s. Formulating the distribution time of the input data, the transfer time of the output data and the time required to compute each algorithm, it estimates total processing time and the number of required DSP. Finally, using the TSG that provides radar control pulses and simulated target signals, performances of the implemented Doppler processor are evaluated.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.6
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• pp.9-19
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• 2002

An NAC(Natural Admittance Control) system design is presented for interaction controller that achieves high-performance and guarantees stability. The NAC can be classified as a particular flavor of impedance control similar to control schemes that have velocity compensator and force compensator. The NAC significantly improves the response characteristics when Coulomb friction is presented in One-link Robot System and guarantees stability when robot contacts with environment. Pragmatic rules for NAC synthesis are derived. It shows method to choose a target impedance for realizable force compensator. Important parameters are found experimentally. It is demonstrated, by the experimental result, that NAC algorithm is successful in rejecting Coulomb friction through velocity compensator and guarantees stability through force compensator. We implement an experimental set-up consisting of environment-generated one-link robot system and DSP system for controller development. We apply the natural admittance controller to the One-link robot system, and show the good performance on desired force control in case of contacting with arbitrary environment.

• JSTS:Journal of Semiconductor Technology and Science
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• v.5 no.3
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• pp.159-167
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• 2005

Quantization effects (QEs), which manifests when the device dimensions are comparable to the de Brogile wavelength, are becoming common physical phenomena in the present micro-/nanometer technology era. While most novel devices take advantage of QEs to achieve fast switching speed, miniature size and extremely small power consumption, the mainstream CMOS devices (with the exception of EEPROMs) are generally suffering in performance from these effects. In this paper, an analytical model accounting for the QEs and poly-depletion effects (PDEs) at the silicon (Si)/dielectric interface describing the capacitance-voltage (C-V) and current-voltage (I-V) characteristics of MOS devices with thin oxides is developed. It is also applicable to multi-layer gate-stack structures, since a general procedure is used for calculating the quantum inversion charge density. Using this inversion charge density, device characteristics are obtained. Also solutions for C-V can be quickly obtained without computational burden of solving over a physical grid. We conclude with comparison of the results obtained with our model and those obtained by self-consistent solution of the $Schr{\ddot{o}}dinger$ and Poisson equations and simulations reported previously in the literature. A good agreement was observed between them.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.5
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• pp.79-89
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• 1984

In this paper we present development of microprocessor-based 8-channel statistical multiplexer (SMUX). The hardware design includes one Z-80A CPU board with the clock rate of 4 MHz, one 16 Kbyte ROM board for program storage, one 16 Kbyte dynamic RAM board and three I/O boards, all connected through an S-100 compatible tristate bus. The SMUX can presently multiplex 8 channels with data rates ranging 50 bps to 9600 bps, but can be reduced to accommodate 4 channels by having a slight modification of software and removing one terminal I/O board. The system specifications meet CCITT recommendations X.25 link level, V.24, V.28, X.3 and X.28. Significant features of the SMUX are its capability of handling 4 input codes (ASCII, EBCDIC, Baudot, Transcode), the use of a dynamic buffer management algorithm, a diagnostic facility, and the efficient use of a single CPU for all system operation. Throughout the paper, detailed explanations are given as to how the hardware and software of the SMUX system have been designed efficiently.

• Journal of Korea Water Resources Association
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• v.46 no.4
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• pp.389-400
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• 2013

In this study, a conventional pipeline unsteady friction model has been integrated into Levenberg Marquardt method to calibrate friction coefficient in a pipeline system. The method of characteristics has been employed as the modeling platform for the frequency dependant model of unsteady friction. In order to obtain Hessian and Jacobian matrix for optimization, the direct differentiation of pressure to friction factor was calculated and sensitivities to friction for heads and discharges were formulated for implementation to the integration constant in the characteristic method. Using a hypothetical simple pipeline system, time series of pressure, introduced by a sudden valve closure, were obtained for various Reynolds numbers. Convergency in fiction factors were evaluated both in steady and unsteady friction models. The comparison of calibration performance between the proposed method and genetic algorithm indicates that faster and stabler behaviour of Levenberg Marquardt method than those of evolutionary calibration.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.6
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• pp.673-679
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• 2014

The important requirements of designing a pattern classifier are high throughput and low memory requirements, and low cost hardware implementation. A pattern classifier by using Multiple Attractor Cellular Automata(MACA) proposed by Maji et al. reduced the complexity of the classification algorithm from $O(n^3)$ to O(n) by using Dependency Vector(DV) and Dependency String(DS). In this paper, we generate a pattern classifier using LFSR to improve efficiently the space and time complexity and we propose a method for finding DV by using the 0-basic path. Also we investigate DV and the attractor of the generated pattern classifier. We can divide an n-bit DS by m number of $DV_i$ s and generate various pattern classifiers.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.2
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• pp.291-298
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• 2020

Sign language was designed for the deaf and dumb people to allow them to communicate with others and connect to the society. However, sign language is uncommon to the rest of the society. The unresolved communication barrier had eventually isolated deaf and dumb people from the society. Hence, this study focused on design and implementation of a wearable sign language interpreter. 6 inertial measurement unit (IMU) were placed on back of hand palm and each fingertips to capture hand and finger movements and orientations. Total of 28 proposed word-based American Sign Language were collected during the experiment, while 156 features were extracted from the collected data for classification. With the used of the long short-term memory (LSTM) algorithm, this system achieved up to 99.89% of accuracy. The high accuracy system performance indicated that this proposed system has a great potential to serve the deaf and dumb communities and resolve the communication gap.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.440-447
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• 2002

This paper considerated about exact flow volume calculation method from factors having an influence on measurement and introduced in anesthesia ventilator realized spirometry system. System used differential pressure sensing method with factors, that is temperature, pressure, gas density, humidity and mucus etc. System optimized for low power system for mobile system. System composed analog interface part, signal processing part, display part. Analog interface part have differential pressure flow sensor and defferential pressure sensor. Signal processing part have AVR processor for low power system display part use serial port (RS232, SPT). so it display at pc monitor or send to anesthesia ventilator. System is stable by linearizing 2th characteristics of flow-differential pressure, auto correction of sensor. Noise reduced by algorithm with analog filter and digital processing. Small, light, low power system is good at mobile system and applied to patient in emergency or mobile. and, System is useful at anesthesia ventilator by using flow sensor.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.12
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• pp.2657-2662
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• 2010

Demand on information security in mobile devices based control system grows rapidly with a view to counteracting information hacking and leakage. Among these techniques, encryption and authentication are most common. This paper presents CBC-MAC (Cipher Block Chaining-Message Authentication Code) based mobile devices control system. The system is termed as Secure Mobile in Vehicle (SMIV)We use CBC-MAC that is one of the most efficient authentication modes to protect information against any malicious attacks. By sharing the secret key of CBC-MAC between the transmitter and receiver, it asserts authentic information. The proposed system is verified in such a way that we develop mobile devices control system, apply the CBC-MAC algorithm to the control system and validate the received data. Unlike conventional systems where the development of control mechanism in mobile devices based control systems is main concern, this proposed system offers a secure communication link of the data in mobile devices control system and therefore would be useful to the design and implementation of various mobile devices based control systems.