• The Korean Journal of Applied Statistics
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• v.24 no.2
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• pp.373-381
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• 2011

This paper discusses how to get the sums of squares due to treatment factors when Type I Analysis is used by projections for the analysis of data under the assumption of a two-way ANOVA model. The suggested method does not need to calculate the residual sums of squares for the calculation of sums of squares. There-fore, the calculation is easier and faster than classical ANOVA methods. It also discusses how eigenvectors and eigenvalues of the projection matrices can be used to get the calculation of sums of squares. An example is given to illustrate the calculation procedure by projections for unbalanced data.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.5
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• pp.725-731
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• 2013

In This paper, through simulation, proposes a system which makes it possible for freely moving multiple agents with ultrasonic receivers to estimate their own position by themselves using the ultrasonic signals sequentially emitted from multiple ultrasonic transmitters. This system possesses an advantage that there is no limit in the number of agents existing in the space covered by more than three transmitters fixed at proper locations. Hence, the proposed system can be utilized effectively in position tracking control of multiple robotic agents system and motion capturing system.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.6
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• pp.674-677
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• 2004

This paper deals with a systematic approach for the construction of the fixed-delay tree search (FDTS) detector in the intersymbol interference channel. The approach is based on the efficient multi-dimensional space partitioning. The Voronoi diagram (VoD) and the Delaunay tessellation (DT) of the multi-dimensional space are applied to implement the algorithm. In the proposed approach, utilizing the geometric information contained in the VOD/DT, the relative location of the observation sequence is determined which has been shown to reduce the implementation complexity. Detailed construction procedures are discussed followed by an example from the intersymbol interference communication channel.

• Journal of Internet Computing and Services
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• v.1 no.1
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• pp.27-34
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• 2000

Recently, the use of Geographic Information System in each field of our society is on the increase according to the development of the Internet. But, thereis a problem of the user access latencies, the network traffic, and the server overload in Internet Geographic Information System because spatial data are transferred in large volumes. In this paper, we propose a cache algorithm on client side to solve the above problems. The proposed algorithm demonstrates the performance improvement over known studies by utilizing unit time and spatial proximity. In addition, this paper conducts a performance evaluation to measure the improvement in algorithm efficiency and analyzes the results of the performance evaluation. When spatial data queries are conducted, according to our performance evaluation, hit rate has been improved over the existing algorithms.

• Journal of Korean Society for Geospatial Information Science
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• v.19 no.3
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• pp.75-82
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• 2011

In this study, author analyzed the overview and the convergence time of Fixed solutions (<15cm) of OmniSTAR, one of SBAS(Satellite Based Augmentation System) as WADGPS (Wide Area Differential GPS), which can compensate the drawbacks of the existed GNSS (Global Navigation Satellite System) that require the expensive receiver and is impossible to position in case of the radio interference in urban sometimes. As a result, the test shows that the less than 15cm 3D standard deviation converges in 39 minutes at Dynamic mode and 28 minutes at Static mode. It is expected that we can apply OmniSTAR to a variety of fields such as LBS(Location Based Service), mobile positioning, and the geo-spatial information industry that does not necessarily guarantee the high position accuracy.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.10 s.340
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• pp.25-30
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• 2005

This paper generalizes the concept of the signal space detection to construct a fixed delay tree search (FDTS) detector which estimates a block of n channel symbols at a time. This technique is applicable to high speed implementation. Two approaches are discussed both of which are based on efficient signal space partitioning. In the first approach, symbol detection is performed based on a multi-class partitioning of the signal space. This approach is a generalization of binary symbol detection based on a two-class pattern classification. In the second approach, binary signal detection is combined with a look-ahead technique, resulting in a highly parallel detector architecture.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.10
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• pp.217-228
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• 2013

In this paper, the brain function in relation with human's visual attention was investigated by means of coherence and bicoherence methods. Throughout experimentation with attentional visual stimulus ERP (Event Related Potential) data and synthesized simulated data with different combinations of parameters, it is demonstrated that bicoherence and coherence can be useful to reveal the phase synchronies between different frequency bands at fixed scalp location, and between different scalp locations at fixed frequency band, respectively. Both methods are also affected by time interval from the onset, and the level of white noise added. The phase coupled relationships among ${\Theta}$, ${\delta}$, and ${\alpha}$ bands, and between frontal and central lobes were observed for attentional tasks, while those were little observable for inattentional tasks, which can show brain's functional spatio-spectral differences associated with human's attention.

• Journal of KIISE:Databases
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• v.37 no.5
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• pp.238-249
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• 2010

Flash memory has been studied as a storage medium in order to improve the performance of the system using its high computing speed in the DBMS field where frequent data access is needed. The most difficulty using the flash memory is the performance degradation and the life span shortening of flash memory coming from inefficient in-place update. Log based approaches have been studied to solve inefficient in-place update problem in the DBMS where write operations occur in smaller size of data than page frequently. However the existing log based approaches suffer from the frequent merging operations, which are the principal cause of performance deterioration. Thus is because their fixed log area management can not guarantee a sufficient space for logs. In this paper, we propose non-fixed log area management technique that can minimize the occurrence of the merging operations by promising an enough space for logs. We also suggest the cost calculation model of the optimal log sector number minimizing the system operation cost in a block. In experiment, we show that our non-fixed log area management technique can have the improved performance compared to existing approaches.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.4
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• pp.351-359
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• 2007

Multi-axial compression tests have been frequently conducted to evaluate the in situ properties of rock masses and the mechanical behaviors of rock strata through the model tests. Without the proper boundary condition for the model tests, the mechanical behavior of rock mass would deviate, as can be expected, from the in situ conditions. The boundary condition will affect the internal stress distribution of the specimens and cause some distortion on the measurement. In this study, a design process regarding the steel brush, which has been employed for multi-axial compression test to reduce the frictional restraint along the specimen/loading platen interface, is introduced. The individual brushes are regarded as a simple column and beam to calculate the cross-sectional size and length of the brushes in consideration of the buckling capacity and the allowable deflection.

• Korean journal of applied entomology
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• v.40 no.2
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• pp.105-109
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• 2001

Dispersion pattern of the citrus red mite (CRM), Panonychus citri (McGregor) was determined to develop a monitoring method in the satsuma mandarin fields, Citrus unshiu L., in Jeju-do, during 1999 and 2000. CRM population was sampled by collecting leaves. Taylor's power law provided better description of mean-variance relationship for the dispersion indices compared to Iwao's patchiness regression. Slopes and intercepts of Taylor's power law from leaf samples did not differ among surveyed groves. Fixed-precision levels (D) of a sequential sampling plan were developed using Taylor's power law parameters generated from all motile stages of CRM in leaf sample. This sampling plan for leaf sample estimate was tested with resampling validation for sampling plan using 4 independent data sets. Resampling simulation analysis demonstrated that actual fixed-precision level values were better than desired D values of 0.20, 0.25 and 0.30. Required numbers for tree sampling at the density of more than 7 mites per tree were fewer than 18.