• Journal of Korea Water Resources Association
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• v.37 no.4
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• pp.329-339
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• 2004

The main objective of this study is to develop a GIS-based two-dimensional model for the simulation of rainfall-runoff process and overland flow of a watershed. The tasks of this study are summarized: to develop a two-dimensional model for overland flow and to construct a rainfall-runoff simulation system linked with GIS. The mathematical formulation of the model incorporates four parts: spatially varied rainfall, spatially distributed infiltration, 1-directional, 4-directional and 8-directional overland flow routing scheme, and one-dimensional channel routing scheme. For the development of stochastic model, Monte Carlo simulation method has been directly integrated into the model. GIS using Arc/Info and ArcView has been applied to prepare the model input data(elevation, soil type, rainfall data, etc.) for a simulation and to demonstrate the simulation results.

• Journal of Korean Society of Transportation
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• v.28 no.4
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• pp.157-166
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• 2010

The aim of this paper was to estimate efficiency using a directional distance function to compare performances of bus agencies to determine if they have made efforts to operate efficiently and reduce emissions and accidents since public transportation reforms 2004. Drivers, mechanics, staff, buses, and fuel were used as input data and vehicle-kilometers (a desirable output), accident costs, and emission costs (undesirable outputs) as output data during June 2005. As a result, the efficiency with undesirable outputs was lower than the efficiency without undesirable outputs. However, the number of efficient agencies was more in case of the consideration of undesirable outputs. The reason is that the number of agencies whose possibility to reduce undesirable outputs are less than the possibility to reduce inputs was increasing, while the efficiency deviation among agencies was larger in case of the consideration of undesirable outputs. Meanwhile, the increase of CNG buses and operating speed and the improvement of mechanical efficiency had positive influence on the efficiency.

• Journal of Information Processing Systems
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• v.18 no.4
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• pp.549-561
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• 2022

In the Khmer writing system, the Khmer script is the official letter of Cambodia, written from left to right without a space separator; it is complicated and requires more analysis studies. Without clear standard guidelines, a space separator in the Khmer language is used inconsistently and informally to separate words in sentences. Therefore, a segmented method should be discussed with the combination of the future Khmer natural language processing (NLP) to define the appropriate rule for Khmer sentences. The critical process in NLP with the capability of extensive data language analysis necessitates applying in this scenario. One of the essential components in Khmer language processing is how to split the word into a series of sentences and count the words used in the sentences. Currently, Microsoft Word cannot count Khmer words correctly. So, this study presents a systematic library to segment Khmer phrases using the bi-directional maximal matching (BiMM) method to address these problematic constraints. In the BiMM algorithm, the paper focuses on the Bidirectional implementation of forward maximal matching (FMM) and backward maximal matching (BMM) to improve word segmentation accuracy. A digital or prefix tree of data structure algorithm, also known as a trie, enhances the segmentation accuracy procedure by finding the children of each word parent node. The accuracy of BiMM is higher than using FMM or BMM independently; moreover, the proposed approach improves dictionary structures and reduces the number of errors. The result of this study can reduce the error by 8.57% compared to FMM and BFF algorithms with 94,807 Khmer words.

• Journal of IKEEE
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• v.28 no.2
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• pp.145-149
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• 2024

Recently, research on temporal action localization has been actively conducted. In this paper, unlike existing methods, we propose two approaches for learning bidirectional information by creating reverse playback videos for fully supervised temporal action localization. One approach involves creating training data by combining reverse playback videos and forward playback videos, while the other approach involves training separate models on videos with different playback directions. Experiments were conducted on the THUMOS-14 dataset using TALLFormer. When using both reverse and forward playback videos as training data, the performance was 5.1% lower than that of the existing method. On the other hand, using a model ensemble shows a 1.9% improvement in performance.

• The Korean Journal of Applied Statistics
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• v.26 no.6
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• pp.873-887
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• 2013

The axis of rotation in biomechanics is a major tool to investigate joint function; therefore, many methods to estimate the axis of rotation have been developed. However, there exist several problems to describe, estimate, and test the axis statistically. The axis is directional data(axial data) and it should not be analyzed with traditional statistics. A proper comparative method should be considered to compare axis estimating methods for the same given data ANOVA (analysis of variance) is a frequently used statistical method to compare treatment means in experimental designs. In case of the axial data response assumed to come from Watson distribution, there are a few ANOVA method options. This study constructed ANOVA models for within-subjects designs of axial data. Two models (one within-subjects factor and two within-subjects factors crossed design) were considered. The empirical data used in this study were instantaneous axes of rotation of flexion/extension at the knee joint and the flexion/extension and pronation/supination at the elbow joint. The results of this study can be further applied to the various analysis of experimental designs.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.323-327
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• 2006

We present the most recent experimental results on Thin-beam Directional X'tallization (TDX), a rapid excimer-laser-based crystallization method for creating extremely high-quality large-grained polycrystalline silicon films on glass substrates. We will present experimental data obtained with our prototype Gen 2 tool, and discuss the ability to produce different types of poly-Si material.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.202-205
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• 1999

• Proceedings of the Korea Database Society Conference
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• 1999.06a
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• pp.353-359
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• 1999

We present a matrix-based inference algorithm suitable for electronic commerce applications. For this purpose, an Extended AND-OR Graph (EAOG) was developed with the intention that fast inference process is enabled within the electronic commerce situations. The proposed EAOG inference mechanism has the following three characteristics. 1. Real-time inference: The EAOG inference mechanism is suitable for the real-time inference because its computational mechanism is based on matrix computation. 2. Matrix operation: All the subjective knowledge is delineated in a matrix form. so that inference process can proceed based on the matrix operation which is computationally efficient. 3. Bi-directional inference: Traditional inference method of expert systems is based on either forward chaining or backward chaining which is mutually exclusive in terms of logical process and computational efficiency. However, the proposed EAOG inference mechanism is generically bi-directional without loss of both speed and efficiency. We have proved the validity of our approach with several propositions and an illustrative EC example.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.50-56
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• 2004

The directional ability of an automobile has an influence on driver directly, and hence it must be given most priority. Alignment factors of automobile such as the camber, caster and toe directly affect the directional ability of a vehicle. The above mentioned factors are determined by the pose of interlinks in the assembly of an automobile front chassis module. Measuring the position of center point of ball joints in the front lower arm is very difficult. A method to determine this position is suggested in this paper. Pose estimation for front chassis module and dimensional evaluation to find the rotational characteristics of front lower arm were developed based on fundamental geometric techniques. To interpret the inspection data obtained for front chassis module, 3-D best fit method is needed. The best fit method determines the relationship between the nominal design coordinate system and the corresponding feature coordinate system. The least squares method based on singular value decomposition is used in this paper.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.2
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• pp.77-87
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• 1996

Existing area-based stereo matching algorithms utilize a single rectangular correlation area for computing cross-correlation between corresponding points in stereo images, and compute disparity by finding the peak in the vicinity of depth discontinuity, since, because of inconstnat disparities around discontinuities, the cross-correlation becomes low in such area. Inthis paper, a new area-based matching strategy is proposed exploiting multiple directional correlation masks instead of a single one. The proposed technique computes multiple cross-covariance functions using each oriented mask. Peaks are detected from each covariance function and the disparity is computed by choosing the location with the highest covariance value. Proposed approach can also be applied to compute disparity gradients without obtaining dense depth data. A number of examples are presented using synthetic and natural stereo images.