• Journal of Korea Water Resources Association
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• v.32 no.2
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• pp.197-210
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• 1999

This study examines the duration and severity of droughts by the use of stochastic process considerations. The key annual flow statistics are used to estimate the related statistics of drought probability distributions for various combinations of return period and water demand. This study efforts initially focused on analyzing all the nation streamgage records that were judged to meet certain selection criteria, including those of record length, record quality. These analyses resulted in the determination of those annual flow statistics necessary to define the behavior of drought sequences for the selected streams. Using prior research results, the actual or estimated flow statistics are related to the probability distributions of maximum drought events, through the application of the theory of runs. This has resulted in assigning return periods to drought events at gaged locations, and permits an assessment of the probabilities of observed historical drought within the nation.

• Journal of Korean Society of Transportation
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• v.8 no.1
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• pp.5-15
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• 1990

As a result of the lack of methodology for the determination of navigational channel capacity and the consequence lack of effective management of traffic, navigational channels are often grossly underutilized or highly congested. The traditional rule of first-come-first-served admission of vessels to channels is not efficient as it assumes equal time intervals between entrance of consecutive vessels. A new vessel traffic management system is developed in this research and methodologies to measure the improvement in the channel capacity are developed. Methodology to measure the channel performances for three queue disciplines are developed. The effects of changes in major factors on the channel capacity model such as channel length, fleet mix and arrival rate, as well as changes in strategy are analyzed. Under given channel conditions, best strategy are recommended. Also, a method for effective stochastic channel capacity simulation was developed. The results of analysis and as ertions are compared with the results of simulation runs to prove their applicability.

• Journal of Korean Port Research
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• v.8 no.2
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• pp.1-35
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• 1994

The main arterial which runs through the in City of Pusan, carries about 60% of downtown traffic or more, maintains about 20% yearly increase in traffic is severely suffering from the traffic congestion because of concentrated traffic volumes regardless of peak-time periods. The purpose of this study was to grasp the traffic, geometric, and signal conditions of the main arterial through the Videologging System Techniques, perform the transportation system analyses, and finally suggest the improvements which could increase the travel capacity, reduce the average delay and fuel consumption with the optimal conditions of signal system. The following conclusions were drawn : firstly the traffic system should be shifted for the travel distribution on the arterial during the peak time periods, secondly the roadway system of the arterial reviewed for left-turn traffic during the peak time periods, and thirdly the signal system of intersection reconstructed for signal optimization or progression within the range of cycle length suggested.

• Proceedings of the Korea Society for Simulation Conference
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• 1999.10a
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• pp.93-99
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• 1999

The service level of Metro stations is affected by the design criteria such as platform area, width and length of stairways, and the number of turnstile, etc. The Korean station design process utilizes peak-hour volume as design volume. Hourly volume, however, can not explicitly account for the variation of traffic and consequently the variation of the level of service within the one-hour time period. Movements in various areas inside of stations are simulated with a queueing network under various operating conditions. A discrete simulation tool called SIMUL8 was utilized. Based on the results, peak volume for 15 minutes period was recommended as a preferred base volume over the peak-hour volume for station design purpose to realistically account for user delays under. Simulation runs also confirmed that escalators have positive effects on passenger processing capacity and on securing stability of passenger flows in stations.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.5
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• pp.260-267
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• 2005

To search efficiently a text T of length n for a pattern P over an alphabet 5, suffix trees and suffix arrays are widely used. In case of a large text, suffix arrays are preferred to suffix trees because suffix ways take less space than suffix trees. Recently, O(${\mid}P{\mid}{\codt}{\mid}{\Sigma}{\mid}$-time and O(${\mid}P{\mid}P{\cdot}log{\mid}{\Sigma}{\mid}$)-time search algorithms in suffix ways were developed. In this paper we present time and space efficient search algorithms in suffix arrays. One algorithm runs in O(${\mid}P{\mid}$) time using O($n{\cdot}{\mid}{\Sigma}{\mid}$)-bits space, and the other runs in O($n{\cdot}{\mid}{\Sigma}{\mid}$ time using O($nlog{\mid}{\Sigma}{\mid}+{\mid}{\Sigma}{\mid}{\cdot}$nlog log n/logn)-bits space, which is more space efficient and still fast. Experiments show that our algorithms are efficient in both time and space when compared to previous algorithms.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.4
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• pp.63-71
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• 1996

In this paper, a variable length block code for real time compression and decompression of hanguel and chinese character bit map font is proposed. The proposed code shows a good compression ratio in complete form of hangeul myoungjo and godik style and chinese batang and doddum style bit map font. Besides, a compression and decompression ASIC is designed and simulated on CAD. The 0.8 micron CMOS sea of gate is used to implement the ASIC in amount of 5,200 gates, and it runs at simple hardware and compress and decompress at 33M bit/sec at maximum, which is ideal for real time applications.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2005.09a
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• pp.147-150
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• 2005

Proper PCR primer design determines the success or failure of Polymerase Chain Reaction (PCR) reactions. In this project, we develop GENE-PRIMER, a genomes specific PCR primer design program that is amenable to a genome-wide scale. To achieve this, we incorporated various parameters with biological significance into our program, namely, primer length, melting temperature of primers Tm, guanine/cytosine (GC) content of primer, homopolymeric runs in primer and self-hybridization tendency of primer. In addition, BLAST algorithm is utilized for the purpose of primer specificity check. In summary, selected primers adhered to both physico-chemical criteria and also display specificity to intended binding site in the genome.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.1221-1226
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• 2001

A structure gauge assessment is needed to ensure that a railway vehicle can run safely along a length of track without coming unacceptably close to lineside structures or equipment, or to vehicles running on adjacent tracks. This apparently straightforward question is in reality very complicated. The amount of space required for the safe passage of a railway vehicle is significantly greater than its static body profile for a number of reasons as follows: as the vehicle runs along the track, the track input excites the vehicle and it moves on its suspension. On curved track its geometric position leads to curve overthrows. A number of different approaches have been used to answer this question and some are described and specially applied to urban train by computer simulation in this paper. The program used for calculating the kinematic and swept envelope is the VAMPIRE made in U.K.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.26 no.4
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• pp.42-49
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• 2003

The branch and bound techniques based on cut tree and eigenvector have been Introduced in the literature [1, 2, 3, 6, 9, 12]. These techniques are used as a basis to allocate departments to floors and then to fit departments with unchangeable dimensions into floors. Grouping algorithms to allocate departments to each floor are developed and branch and bound forms the basis of optimizing using the criteria of rectilinear distance. The proposed branch and bound technique, in theory, will provide the optimal solution on two dimensional layout. If the runs are time and/or node limited, the proposed method is a strong heuristic The technique is made further practical by the fact that the solution is constrained such that the rectangular shape dimensions length and width are fixed and a perfect fit is generated if a fit is possible. Computational results obtained by cut tree-based algorithm and eigenvector-based algorithm are shown when the number of floors are two or three and there is an elevator.

• Phonetics and Speech Sciences
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• v.6 no.2
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• pp.9-20
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• 2014

In this paper, we propose an automatic fluency evaluation algorithm for English speaking tests. In the proposed algorithm, acoustic features are extracted from an input spoken utterance and then fluency score is computed by using support vector regression (SVR). We estimate the parameters of feature modeling and SVR using the speech signals and the corresponding scores by human raters. From the correlation analysis results, it is shown that speech rate, articulation rate, and mean length of runs are best for fluency evaluation. Experimental results show that the correlation between the human score and the SVR score is 0.87 for 3 speaking tests, which suggests the possibility of the proposed algorithm as a secondary fluency evaluation tool.