• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.10
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• pp.1433-1443
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• 1993

DCT(Discrete Cosine Transform) / IDCT(Inverse DCT) is widely used in various image compression and decompression systems as well as in DSP(Digital Signal Processing) applications. Since DCT/ IDCT is one of the most complicated part of the compression system, the performance of the system can be greatly enchanced by improving the speed of DCT/IDCT operation. In this thesis, we designed a DCT/IDCT core processor using module generator technique. By utilizing the partial sum and DA(Distributed Arithmetic) techniques, the DCT/ IDCT core processor is designed within small area. It is also designed to perform the IDCT(Inverse DCT) operation with little additional circuitry. The pipeline structure of the core processor enables the high performance, and the high accuracy of the DCT/IDCT operation is obtained by having fewer rounding stages. The proposed design is independent of design rules, and the number of the input bits and the accuracy of the internal calculation coa be easily adjusted due to the module generator technique. The accuracy of the processor satisfies the specifications in CCITT recommendation H, 261.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.12
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• pp.10-19
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• 2001

In this paper, we propose an effective but simple multi-rate parallel interference canceller(PIC) for the international mobile telecommunications-2000(IMT-2000) 3rd generation partnership project (3GPP) system. For effective multi-rate processing, we define the basic block as one symbol period of the dedicated physical control channel(DPCCH) having the lowest data rate and common to all users. Then, decision and interference cancellation are performed at every basic block. For an asynchronous channel, we propose an advance removal scheme that removes in advance multiple access interference(MAI) due to the next blockof other users with shorter delay. Introducing a pipeline structure at a sample base, we can implement efficiently the PIC using the advance removal scheme with a minimum hardware and no extra computations. Through computer simulations, we analyze the bit error rate(BER) performance of the proposed PIC with respect to signal-to-noise ratio(SNR) and the number of users.

• Journal of the Korea Society of Computer and Information
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• v.19 no.12
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• pp.133-141
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• 2014

An efficient method for reducing power consumption in pipelined deep packet inspection systems is proposed. It is based on the observation that the number of memory accesses is dominant for the power consumption and the number of accesses drops drastically as the input goes through stages of the pipelined AC-DFA. A DPI system is implemented where the operating frequency of the stages that are not frequently used in the pipeline is reduced to eliminate the waste of power consumption. The power consumption of the proposed DPI system is measured upon various input character set and up to 25% of reduction of total power consumption is obtained, compared to those of the recent DPI systems. The method can be easily applied to other pipelined architecture and string searching applications.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.2
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• pp.177-186
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• 2002

This paper describes the magnetic flux leakage(MFL) type non-destructive testing(NDT) system to detect the 3D defects in underground gas pipe. Magnetic systems with permanent magnets and yokes are analyzed by 3D non-lineal finite element method(FEM) with optimum design. In case of under-saturation of gas pipe, sensing signals are too weak to detect. In case of over-saturation, the changes of the sensing signals are too low to detect the defects sensitively. So, the operating points of the magnetic system are optimized to increase the changes of the MFL signals. The effects of the depth and size of the defects on the sensing signals are analyzed to define the range and resolution of the MFL sensors. To increase the sensor's sensitivity, the back-yoke sensors are introduced and tested.

• Korean Journal of Veterinary Service
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• v.17 no.3
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• pp.208-226
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• 1994

From January to December 1993, 3,385 bulk milk samples were collected from 293 herds in Inchon area. Standard plate counts(SPC) and somatic cell counts(SCC) were performed by the method of milk collection, the situation of raising management and monthly. The results obtained are summarized as follows : 1, Annual average SPC and SCC were respectively 638,000 cfu /mm and 647,000 cells /mm. SPC showed an abrupt decrease from January-1,088,000 cfu /mm to December-279,000 cfu /mm, but SCC showed a slow change from January-1,017,000 cells /mm to December -673,000 cells /mm 2. Variation on milk quality(annual average SPC) was shown a wide difference between everyday collection-575,000 cfu /mm and every other day collection-1,243,000 cfu /mm ac-cording to frequency of milk collection from dairy farms. However, there was a little difference In SCC. 3. In the raising scale, average SPC were the lowest in 16~25mi1king cows, and average SCC were the lowest in above 25milking cows. 4. According to types of milking machine, average SPC and SCC of dairy farms that are equipped with pipeline system were respectively 361,000 cfu /mm and 591,000 cells /mm. Those of dairy farms with bucket system were 549,000 cfu /me and 559,000 cells /mm. 5. In the types of management, average SPC an SCC of dairy farms with hired herdsman were 288,000 cfu /mm and 559,000 cells /mm. Those of dairy farms with self-management were 526,000 cfu /mm and 568,000 cells /mm.

• Journal of the Korean Institute of Gas
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• v.12 no.1
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• pp.19-24
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• 2008

Due to industrialization and urbanization, underground metallic utilities with different owners have been rapidly increased and cathodic protection (CP) methods, especially impressed current CP systems, have been widely adopted to protect their utilities from corrosion with expanded recognition of this method. The stray current interference problem as well as the difficulty in spatial security for system installation, however, came to a ramification of which each owner couldn't resolve for himself. In this respect, this paper illustrates a field-diagnosed example for mutual interference due to separately operated CP systems and suggests an alternative method to overcome the interference situation by design and field-assessment of a common anode bed cathodic protection system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.3
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• pp.587-594
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• 2005

In the paper, after we propose a viterbi decoder which has multiple buffering and parallel processing decoding scheme through expanding time-divided imput signal, and map a FPGA, we implement a channel coding system together with PC-based software. Continuous input signal is buffered as order of decoding length and is parallel decoded using a high speed cell for viterbi decoding. Output data rate increases linearly with the cell formed the viterbi decoder, and flexible operation can be satisfied by programming controller and modifying input buffer. The tell for viterbi decoder consists of HD block for calculating hamming distance, CM block for calculating value in each state, TB block for trace-back operation, and LIFO. The implemented cell of viterbi decoder used 351 LAB(Logic Arrary Block) and stably operated in maximum 139MHz in APEX20KC EP20K600CB652-7 FPGA of ALTERA. The whole viterbi decoder including viterbi decoding cells, input/output buffers, and a controller occupied the hardware resource of $23\%$ and has the output data rate of 1Gbps.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.10C
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• pp.1025-1031
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• 2007

This paper proposes an area-efficient pipeline FFT processor for MIMO-OFDM systems with four transmitting and four receiving antennas. Since the MIMO-OFDM system transmits multiple data streams, the complexity for the MIMO-OFDM system with a single-channel FFT processor increases linearly with the increase of the number of transmit channels. The proposed FFT processor is based on multi-channel structure, and therefore it can efficiently support multiple data streams. With the mixed radix algorithm, the number of non-trivial multiplications of the proposed FFT processor is decreased. The proposed FFT processor is synthesized with CMOS $0.18{\mu}m$ process and reduces the logic gates by 25% over a 4-channel Radix-4 multi-path delay commutator (R4MDC) FFT processor. Since the MIMO-OFDM FFT processor is one of the largest modules in the systems, the proposed FFT processor will be a vast contribution improvement to the low complexity design of MIMO-OFDM systems.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.1
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• pp.44-52
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• 2014

Leakage is an important factor to be considered for the management of underground water supply pipelines in a smart water grid system, especially if the pipelines are aged and buried under the pavement or various structures of a highly populated city. Because the exact detection of the location of such leaks in pipelines is essential for their efficient operation, a new methodology for leak location detection based on frequency band variation, windowing filters, and probability is proposed in this paper. Because the exact detection of the leak location depends on the precision of estimation of time delay between sensor signals due to leak noise, some window functions that offer weightings at significant frequencies are applied for calculating the improved cross-correlation function. Experimental results obtained by applying this methodology to an actual buried water supply pipeline, ~ 253.9 m long and made of cast iron, revealed that the approach of frequency band variation with those windows and probability offers better performance for leak location detection.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.2 s.29
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• pp.127-132
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• 2007

This study is to determine an optimal reservoir among many alternative proposals in order to obtain the maximized efficiency under the limited budget. There are many alternative proposals which deal with problems to assign reservoir such as water conversion establishment construction, subterranean water, reservoir, submarine pipeline, water boat, and marine water saving base construction. In this paper, the new model to assign the most reasonable alternative is introduced using 0-1 integer programming. This proposed model has not been applied in the optimal reservoir selection problem yet. This paper will contribute to determine the most reasonable alternative to minimize budget under constraints. Also, this proposal model can be applied to other reservoir selection problem in other regions.