• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.54 no.9
• /
• pp.531-538
• /
• 2005

This paper proposes an expert system which is able to enhance the accuracy and productivity by determining the test strategy based on heuristic rules for test of the hybrid electronic circuit board producted massively in production line. The test heuristic rules are obtained from test system designer, test experts and experimental results. The guarding method separating the tested device with circumference circuit of the device is adopted to enhance the accuracy of measurements in the test of analog devices. This guarding method can reduce the error occurring due to the voltage drop in both the signal input line and the measuring line by utilizing heuristic rules considering the device impedance and the parallel impedance. Also, PSA(Parallel Signature Analysis) technique Is applied for test of the digital devices and circuits. In the PSA technique, the real-time test of the high integrated device is possible by minimizing the test time forcing n bit output stream from the tested device to LFSR continuously. It is implemented in Visual C++ computer language for the purpose of the implementation of the inference engine using the dynamic memory allocation technique, the interface with the electronic circuit database and the hardware direct control. Finally, the effectiveness of the builded expert system is proved by simulating the several faults occurring in the mounting process the electronic devices to the surface of PCB for a typical hybrid electronic board and by identifying the results.

• Journal of the Korean Society for Library and Information Science
• /
• v.21
• /
• pp.249-290
• /
• 1991

Theoretical developments in the information retrieval have offered a number of alternatives to traditional Boolean retrieval. Probability theory and fuzzy set theory have played prominent roles here. Fuzzy set theory is an attempt to generalize traditional set theory by permitting partial membership in a set and this means recognizing different degrees to which a document can match a request. In this study, an experimentation of a document retrieval system using the fuzzy relation matrix of the keywords is described and the results are offered. The queries composed of keywords and Boolean operaters AND, OR, NOT were processed in the retrieval method, and the method was implemented on the PC of 32bit level (30 MHz) in an experimental system. The measurement of the recall ratio and precision ratio verified the effectiveness of the proposed fuzzy relation matrix of keywords and retrieval method. Compared to traditional crisp method in the same document database, the recall ratio increased $10\%$ high although the precision ratio decreased slightly. The problems, in this experiment, to be resolved are first, the design of the automatic data input and fuzzy indexing modules, through which the system . can have the ability of competition and usefulness. Second, devising a systematic procedure for assigning fuzzy weights to keywords in documents and in queries.

• Journal of the Korean Society of Safety
• /
• v.27 no.6
• /
• pp.48-53
• /
• 2012

This paper is purposed to develop portable electric instrument to select NI-9223(National instrument comp.) and clamp meter(HIOKI comp.), which can be used in developing electric instrument, to detect leakage current(ZCT) and current(CT) signals. In this paper, The electric instrument that can interface with current and leakage current instrument(HIOKI 9283), is developed by NI-9223 of NI comp.. HIOKI clamp meter can measure current signals certainly by high-sensitivity of 10 ${\mu}A$ resolution(leakage current : at 10 mA range) and current 1~200A range. The NI-9223 use four 16-bit analog-to-digital converters(ADCs) for true simultaneous sampling at up to 1 MS/s per channel. NI-9223 can synchronize all analog input modules installed in the same chassis to share the same start clock and/or sample clocks. The monitoring program is developed by SignalExpress of LabVIEW. The monitoring program are developed to analyze at simultaneous sampling on electrical signals such as leakage current(ZCT) and current(CT). The developed system verification tests were conducted, and portable electric instrument can be used in place which requires analysis of the actual electrical signal.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.2 no.3
• /
• pp.335-341
• /
• 1998

In this paper, we present a real time implementation of CS-ACELP(Conjugate Structure Algebraic Code Excited Linear Prediction) speech coder. ITU-T has standardized the CS-ACELP algorithm as G.729. Areal-time implementation of CS-ACELP speech coder algorithm is achieved using 16 bit fixed-point DSP chip. To implement in fixed-point DSP Chip, integer simulation of CS-ACELP algorithm is used. Furthermore. input/output function and communication function included in CS-ACELP speech coder is described. We develope CS-ACELP speech coder in DSP evaluation board and evaluate in IMT-2000 Test-bed.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.3
• /
• pp.432-440
• /
• 2015

We investigate BER performance according to the order of spatial and frequency diversity combining in uplink SC-FDMA of SIMO systems. It is found that frequency diversity combining (FDC) after spatial diversity combining (SDC) is better than the reverse order combing in all SNR (Signal to Noise Ratio) range. Also, it is shown that FDC after SDC requires less computational complexity than the reverse order combining.

• Journal of Communications and Networks
• /
• v.13 no.5
• /
• pp.442-448
• /
• 2011

It's a challenging task to design a high performance modulation for satellite and space communications due to the limited power and bandwidth resource. Constant envelope modulation is an attractive scheme to be used in such cases for their needlessness of input power back-off about 2~3 dB for avoidance of nonlinear distortion induced by high power amplifier. The envelope of Feher quadrature phase shift keying (FQPSK) has a least fluctuation of 0.18 dB (quasi constant envelope) and can be further improved. This paper improves FQPSK by defining a set of new waveform functions, which changes FQPSK to be a strictly constant envelope modulation. The performance of the FQPSK adopting new waveform is justified by analysis and simulation. The study results show that the novel FQPSK is immune to the impact of HPA and outperforms conventional FQPSK on bit error rate (BER) performance. The BER performance of this novel modulation is better than that of FQPSK by more than 0.5 dB at least and 2 dB at most.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.2
• /
• pp.552-557
• /
• 2000

In the paper, we proposed a face recognition method that uses GA-BP(Genetic Algorithm-Back propagation Network) that optimizes initial parameters such as bias values or weights. Each pixel in the picture is used for input of the neuralnetwork. The initial weights of neural network is consist of fixed-point real values and converted to bit string on purpose of using the individuals that arte expressed in the Genetic Algorithm. For the fitness value, we defined the value that shows the lowest error of neural network, which is evaluated using newly defined adaptive re-learning operator and built the optimized and most advanced neural network. Then we made experiments on the face recognition. In comparison with learning convergence speed, the proposed algorithm shows faster convergence speed than solo executed back propagation algorithm and provides better performance, about 2.9% in proposed method than solo executed back propagation algorithm.

• The KIPS Transactions:PartA
• /
• v.14A no.3 s.107
• /
• pp.147-150
• /
• 2007

This paper describes a new low-swing inverter for low power consumption. To reduce a power consumption, an output voltage swing is in the range from 0 to VDD-2VTH. This can be done by the inverter structure that allow a full swing or a swing on its input terminal without leakage current. Using this low-swing voltage technology, we proposed a low-power 16$\times$16 bit parallel multiplier. The proposed circuits are designed with Samsung 0.35$\mu$m standard CMOS process at a 3.3V supply voltage. The validity and effectiveness are verified through the HSPICE simulation.. Compared to the previous works, this circuit can reduce the power consumption rate of 17.3% and the power-delay product of 16.5%.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.10
• /
• pp.1460-1468
• /
• 2015

As the number of IoT service increases, the interest of lightweight block cipher algorithm, which consists of simple operations with low-power and high speed, is growing. LEA(Leightweight Encryption Algorithm) is recently adopted as one of lightweight encryption standards in Korea. In this paper a pipeline LEA architecture is proposed to process large amounts of data with high throughput. The proposed pipeline LEA can communicate with external modules in the 32-bit I/O interface. It consists of input, output and encryption pipeline stages which take 4 cycles using a muti-cycle pipeline technique. The experimental results showed that the proposed pipeline LEA achieved more than 7.5 Gbps even though the key length was varied. Compared with the previous high speed LEA in accordance with key length of 128, 192, and 256 bits, the throughput of the pipeline LEA was improved 6.45, 7.52, and 8.6 times. Also the throughput per area was improved 2, 1.82, and 2.1 times better than the previous one.

• MALSORI
• /
• no.61
• /
• pp.75-86
• /
• 2007

In this paper, we propose a scalable audio coder, which has a variable bandwidth from the narrowband speech bandwidth to the audio bandwidth and also has a bit-rate from 8 to 320 kbits/s, in order to cope with the quality of service(QoS) according to the network load. First of all, the proposed scalable coder splits bandwidth of the input audio into narrowband up to around 4 kHz and above. Next, the narrowband signals are compressed by a speech coding method compatible to an existing standard speech coder such as G.729, and the other signals whose bandwidth is above the narrowband are compressed on the basis of a psychoacoustic model. It is shown from the objective quality tests using the signal-to-noise ratio(SNR) and the perceptual evaluation of audio quality(PEAQ) that the proposed scalable audio coder provides a comparable quality to the MPEG-1 Layer III (MP3) audio coder.