• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.2
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• pp.41-47
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• 2016

The times of multiplication for encryption and decryption of cryptosystem is primarily determined by implementation efficiency of the modular exponentiation of $a^b$(mod m). The most frequently used among standard modular exponentiation methods is a standard binary method, of which n-ary($2{\leq}n{\leq}6$) is most popular. The n-ary($1{\leq}n{\leq}6$) is a square-and-multiply method which partitions $b=b_kb_{k-1}{\cdots}b_1b_{0(2)}$ into n fixed bits from right to left and squares n times and multiplies bit values. This paper proposes a variable-length partition algorithm that partitions $b_{k-1}{\cdots}b_1b_{0(2)}$ from left to right. The proposed algorithm has proved to reduce the multiplication frequency of the fixed-length partition n-ary method.

• Proceedings of the Korea Association of Information Systems Conference
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• 2000.11a
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• pp.1.2-24
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• 2000

The field of neural networks has been a recent surge in activity as a result of progress in developments of efficient training algorithms. For this reason, and coupled with the widespread availability of powerful personal computer hardware for running simulations of networks, there is increasing focus on the potential benefits this field can offer. The neural network may be viewed as an advanced pattern recognition technique and can be applied in many areas such as financial time series forecasting, medical diagnostic expert system and etc.. The intention of this study is to build and implement one simple artificial neural networks hereinafter called ANN. For this purpose, some literature survey was undertaken to understand the structures and algorithms of ANN theoretically. Based on the review of theories about ANN, the system adopted 3-layer back propagation algorithms as its learning algorithm to simulate one case of medical diagnostic model. The adopted ANN algorithm was performed in PC by using turbo PASCAL and many input parameters such as the numbers of layers, the numbers of nodes, the number of cycles for learning, learning rate and momentum term. The system output more or less successful results which nearly agree with goals we assumed. However, the system has some limitations such as the simplicity of the programming structure and the range of parameters it can dealing with. But, this study is useful for understanding general algorithms and applications of ANN system and can be expanded for further refinement for more complex ANN algorithms.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.4
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• pp.112-119
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• 2017

Selecting suppliers in the global supply chain is the very difficult and complicated decision making problem particularly due to the various types of supply risk in addition to the uncertain performance of the potential suppliers. This paper proposes a multi-phase decision making model for supplier selection under supply risks in global supply chains. In the first phase, the model suggests supplier selection solutions suitable to a given condition of decision making using a rule-based expert system. The expert system consists of a knowledge base of supplier selection solutions and an "if-then" rule-based inference engine. The knowledge base contains information about options and their consistency for seven characteristics of 20 supplier selection solutions chosen from articles published in SCIE journals since 2010. In the second phase, the model computes the potential suppliers' general performance indices using a technique for order preference by similarity to ideal solution (TOPSIS) based on their scores obtained by applying the suggested solutions. In the third phase, the model computes their risk indices using a TOPSIS based on their historical and predicted scores obtained by applying a risk evaluation algorithm. The evaluation algorithm deals with seven types of supply risk that significantly affect supplier's performance and eventually influence buyer's production plan. In the fourth phase, the model selects Pareto optimal suppliers based on their general performance and risk indices. An example demonstrates the implementation of the proposed model. The proposed model provides supply chain managers with a practical tool to effectively select best suppliers while considering supply risks as well as the general performance.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1135-1142
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• 2017

In this paper, we propose an algorithm that can automatically mix the screen and sound by tracking the change of the sound data according to the screen change so that the real sound can be implemented in the personal broadcasting service. Since the personal broadcasting service is often broadcasted lively, it should be convenient to have a real-time mixing. Through experiments, it was confirmed that the sound pressure changes in a wide range in the high frequency band related to the clarity for understanding according to the rotation angle change of the screen. Regression analysis of the sound pressure changes at 2kHz, 4kHz, and 8kHz, The attenuation change of sound pressure was observed at the slope of -1.17, the slope of -2.0, and the slope of -2.44 for each frequency. Therefore, these experiment results can be applied to the VR service. This study is expected to be useful data in the implementation of personal broadcasting service.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1159-1166
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• 2017

Cattle behavior detection system based on Internet of Things is designed and implemented by using gyroscope and acceleration sensor, Arduino pro-mini and bluetooth module. The implemented system measures cattle's moving and the measured data are transmitted to smart phone by bluetooth module. They are displayed by 2-dimensional graph on the smart phone and the number of cattle's step are calculated from the graph. The detected and gathered data from the system are analyzed by the proposed algorithm to decide which cows are in the estrus or not, and the proposed system can be used to increase the success rate of artificial insemination in normal estrus by detecting cow's behaviors such as the number of steps and jumping. In this paper, the implemented cattle behavior detecting system are strapped on cattle's leg and it measures cattle behaviors for determining that a cattle is estrus or not by the proposed algorithm. In the future research, the system which lengthens communication distance and increases the number of cattle under the test will be considered and also the measured data will be database for cattle research.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.257-260
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• 2002

This paper describes a design of cryptographic processor that implements the AES (Advanced Encryption Standard) block cipher algorithm“Rijndael”. To achieve high throughput rate, a sub-pipeline stage is inserted into the round transformation block, resulting that the second half of current round function and the first half of next round function are being simultaneously operated. For area-efficient and low-power implementation the round transformation block is designed to share the hardware resources in encryption and decryption. An efficient scheme for on-the-fly key scheduling, which supports the three master-key lengths of 128-b/192-b/256-b, is devised to generate round keys in the first sub-pipeline stage of each round processing. The cryptoprocessor designed in Verilog-HDL was verified using Xilinx FPGA board and test system. The core synthesized using 0.35-${\mu}{\textrm}{m}$ CMOS cell library consists of about 25,000 gates. Simulation results show that it has a throughput of about 520-Mbits/sec with 220-MHz clock frequency at 2.5-V supply.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.3
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• pp.279-287
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• 2010

Interior permanent magnet synchronous motor(IPMSM) adjustable speed drives offer significant advantages over induction motor drives in a wide variety of industrial applications such as high power density, high efficiency, improved dynamic performance and reliability. This paper proposes efficiency optimization control of IPMSM drive using adaptive fuzzy learning controller(AFLC). In order to optimize the efficiency the loss minimization algorithm is developed based on motor model and operating condition. The d-axis armature current is utilized to minimize the losses of the IPMSM in a closed loop vector control environment. The design of the current based on adaptive fuzzy control using model reference and the estimation of the speed based on neural network using ANN controller. The controllable electrical loss which consists of the copper loss and the iron loss can be minimized by the optimal control of the armature current. The minimization of loss is possible to realize efficiency optimization control for the proposed IPMSM. The optimal current can be decided according to the operating speed and the load conditions. This paper considers the design and implementation of novel technique of high performance speed control for IPMSM using AFLC. Also, this paper proposes speed control of IPMSM using AFLC1, current control of AFLC2 and AFLC3, and estimation of speed using ANN controller. The proposed control algorithm is applied to IPMSM drive system controlled AFLC, the operating characteristics controlled by efficiency optimization control are examined in detail.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12C
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• pp.1193-1200
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• 2005

In this paper, we proposed an image hiding method which decreases the amount of calculation encrypting partial data rather than the whole image data using a discrete wavelet transform and a linear scalar quantization which have been adopted as the main technique in JPEG2000 standard and then implemented the proposed algorithm to hardware. A chaotic system was used instead of encryption algorithms to reduce further amount of calculation. It uses a method of random changing method using the chaotic system of the data in a selected subband. For ciphering the quantization index it uses a novel image encryption algorithm of cyclical shifting to the right or left direction and encrypts two quantization assignment method (Top-down coding and Reflection coding), made change of data less. The experiments have been performed with the proposed methods implemented in software for about 500 images. The hardware encryption system was synthesized to find the gate-level circuit with the Samsung $0.35{\mu}m$ Phantom-cell library and timing simulation was performed, which resulted in the stable operation in the frequency above 100MHz.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.7A
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• pp.994-1004
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• 2000

In this paper, bitstreams are composed of using H.263 for a moving picture coding in the band-limited and error-prone environment such as wireless environment. EREC sub-frames are implemented by applying the proposed EREC algorithm in order to be UEP for the real data parts of implemented bitstreams. Because those are able to do resynchronization with a block unit, propagation of the error can be minimized, and the position of the important bits such as INTRADC and MVD can be known. Class is separated using the position of these important bits, and variable puncturing tables are designed by the class informations and the code rates of turbo codes are differently designed in according to the class. Channel coding used the turbo codes, and an interleaver to be designed in the turbo codes does not eliminate redundancy bits of the important bits in applying variable code rates of EREC sub-frames unit and is always the same at the transmitter and the receiver although being variable frame size. As a result of simulation, UEP with the code rate similar to EEP is obtained a improved result in the side of bit error probability. And the result of applying it to image knows that the subjective and objective quality have been improved by the protection of important bits.

• Journal of the Korea Society of Computer and Information
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• v.12 no.5
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• pp.19-27
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• 2007

We have implemented a WWW homepage which finds an optimal route for users. There already exist many web sites which provide the optimal route when a start and a destination cities are given. However, none of them can find the optimal route when a number of cities to be visited. The problem of finding the optimal route starting at a given start city and visiting through all the given intermediate cities and finally returning to the start city is called Travelling Sales Person(TSP) problem. TSP is a well known exponential time complexity problem. We have implemented an artificial intelligent search algorithm for TSP on our homepage. The main feature of our algorithm is that the destination may not be the same as the start city whereas all of the existing heuristic algorithms for TSP assume that the start and the destination cities are the same. The web page asks a user to select all the cities he or she wants to visit(including start and destination city), then it finds a sequence of the cities such that the user would travel minimum distance if he or she visits the cities in the order of the sequence. This paper presents algorithms used in the homepage.