• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.3
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• pp.1492-1509
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• 2017

The wireless sensor network (WSN) is a key technology to support the Internet of things (IoT) paradigm. The efficiency of the MAC protocol in WSN is very important to take scalability with restricted wireless resources. The DESYNC-TDMA has an advantage of simple distributed slot allocation inspired by nature, but there is a critical disadvantage of split slots by firing message. The basic split slot model has less efficiency for continuous packet transmitting because of wasting of the slots less than the packet size. In this paper, we propose a firing offset adjustment scheme to improve the efficiency of slot utilizations, which can manage the slot assigned to each node as a single large block, called the single slot model. The performance analysis models for both the existing and the proposed schemes are also derived. Experimental results show that the proposed method provide better efficiency of slot utilization than the existing schemes without any loss of the nature of the desynchronization.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.9 no.1
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• pp.47-54
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• 1991

In this study, the accuracy of three dimensional location was improved by self calibration bundle method with additional parameter, which is to correct systematic error through detection and elimination of the gross error from updated reference variance for observation values in photogram-metry. In this study, with the result of comparing accuracy of each method, correcting systematic error is more effective after gross error detection and when observation values are contained more than two gross error the point with maximum correlation value is detected by masking effect of least square adjustment.

• Water for future
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• v.26 no.3
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• pp.125-135
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• 1993

This study was conducted for two purposes. The first was the selection of the proper model for the urban runoff, and NPS(non-point source) loads and the second was the adjustment of the selected model through the calibration and the verification of the observed data on an urban drainage basin. The selected model for this study was the Storm Water Management Model(SWMM) developed and maintained by the US Environmental Protection Agency(EPA). In particular, the Runoff Block for the surface discharge and the Transport Block for the flow routing was used. The study basin is Youngdu basin, which is a typical developed urban drainage basin. The four rainfall events for the runoff and the two for the four NPS pollutants(SS, BOD, COD and TN) were used for the calibration and the estimation of the model parameters. This study performed the calibration with regard to the peak discharge, the time to peak discharge, the volume and the relative error for three items. It was shown that SWMM can successfully be used for the prediction of the runoff and the NPS pollutants discharge. The result of this study can be used as the basis for the analysis of the correlation between the runoff and the NPS pollutants discharges, and the analysis of the mass balance with the monthly and annual NPS loads in an urban drainage basin.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4A
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• pp.307-314
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• 2010

In this paper, a receive diversity combining technique is proposed for single-carrier frequency division multiple access (SC-FDMA)-based cooperative relay systems when discrete Fourier transform (DFT) spreading sizes for mobile station (MS) and relay station (RS) are different. The proposed technique is composed of a DFT spreading size adjustment block, a phase rotation compensation block, a channel phase compensation block, and a receive diversity combining block. The proposed technique is robust to multipath channels and can be operated with a relatively small computational complexity because receive diversity combining is performed with scalar operations in the frequency-domain. It is shown by computer simulation that the proposed receive diversity combining techniques achieve a performance gain over the conventional maximal ratio combining (MRC) techniques for SC-FDMA-based cooperative relay systems.

• The KIPS Transactions:PartA
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• v.16A no.2
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• pp.89-100
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• 2009

With the advance in digital technologies and the increasing prevalence of high quality multimedia contents, there is a growing user demand for multimedia devices, such as mobile phones, digital TV, PMP, digital camcoders, digital cameras. Such devices provide various services associated with multimedia file manipulation, including multimedia contents playback, multimedia file editing, etc. Conventional file systems exhibit a performance-related drawback that requires considerable amount of time and disk I/Os in order to store large-sized edited multimedia files. This paper proposes a fast, efficient writing technique for large-sized edited multimedia files by using data block sharing with adjustment of inode block pointers. Our experiments show that the proposed scheme not only improves write performance of the Ext3 file system on average by 16 times with various types of edited multimedia files, but also reduces consumed disk space dramatically through the data block sharing.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.7 no.2
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• pp.35-43
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• 1989

The improvements of highly accurate and dense control networks are major requirements to carry out numerical surveying and a large scale mapping for cadastral renovation. In the most conventional photogrammetric solutions, adjusted control coordinates have been applied to block triangulations. However, this study, imploying real data and those of simulated as well, contributes to a simultaneously combined adjustment. It also contains such photogrammetric as photocoordinates and geodetic observations like distances, angles and hight differences. Its purpose is to introduce the improved results, despite it is not sufficient for the ground network. In addition, through the detection of gross error, more precise observational data can be selected for the better adjustment. All in all, the result of this study can be summarized as follows : First, even if the ground control points are not sufficient nor existed at all, the combination of pbotogrammetric and geodetic observations are improved its accuracy. Secondly, the case #2 is more accurate than that of #3, and the case #7 comes into close to that of #6.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.2
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• pp.203-211
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• 2009

With supply of the domestic digital camera, the relative importance of the digital camera is coming to be high gradually on aerial photogrammetry, the image of digital camera is more applied in image map or digital topographic map production. But, there are cases that do not have position information or attitude information of each photograph in digital camera results. Therefore, we wish to present additional method to get more accurate photograph control point result. In this study, One is called A method, which is the case of entering positioning information of principal point from topographic map as default values that are need to extract tie point automatically using by 56 pieces of photography that are photographed by DMC to the extent to 5 courses and 35 GCP points. The other is called B-method, which is the case of entering exterior orientation parameters that are processed by block adjustment for A-method using by 4 control points in method-1 as default values. We have analyzed about results per control points arrangement for two cases using MATCH-AT that is photograph control point measurement S/W of Germany INPHO company. As a result of analysis, accuracy of B-method was better than that of A-method, and we could get more accurate results if block adjustments are executed including self calibration. Also, it is more effective in expense side that using self calibration for photograph survey in B-method because can reduce GCP numbers.

• Journal of the korean academy of Pediatric Dentistry
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• v.21 no.2
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• pp.577-585
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• 1994

The Twin Blocks technique was developed by Dr. William Clark of Scotland during the early 1980's. Twin Blocks are an uncomplicated system that incorporates the use of upper and lower bite blocks. These blocks reposition the mandible and redirect occlusal forces to achieve rapid correction of malocclusions. They are also comfortable and the patients wear them full-time-inducing eating time. Occlusal forces transmitted through the dentition provide a constant proprioceptive stimulus to influence the rate of growth and the trabecular structure of the supporting bone. The features of Twin Blocks mean easier and quicker treatment. The occlusal inclined plane is the fundamental functional mechanism of the natural dentition. Twin blocks are bite blocks that effectively modify the occlusal inclined plane to induce favorably directed occlusal forces by causing a functional mandibular displacement. Upper and lower bite blocks interlock at a $45^{\circ}$ angle and are designed for full-time wear to take advantage of all functional forces applied to the dentition including the forces of mastication. The patients who were treated with modified Twin Blocks, and following results were observed: 1. Large overjet and deep overbite were corrected. 2. Class II molar relationship was changed into Class I. 3. Labial inclination of upper incisors was corrected by adjustment of labial bow of upper bite block. 4. The profiles of two patients were improved by anterior displacement of mandible.

• Journal of Ocean Engineering and Technology
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• v.23 no.2
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• pp.87-91
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• 2009

The welding distortion of a hull structure in the shipbuilding industry is inevitable at each assembly stage. The geometric inaccuracy caused by welding distortion tends to preclude the introduction of automation and mechanization and requires additional man-hours for adjustment work during the following assembly stage. To overcome this problem, a distortion control method should be applied. For this purpose, it is necessary to develop an accurate prediction method that can explicitly account for the influence of various factors on the welding distortion. The validity of this prediction method must also be clarified through experiments. For the purpose of reducing the weld-induced bending deflection, this paper proposes the plastic counter-deforming method (PCDM), which uses line heating as the optimum distortion control method. The validity of this method was substantiated by a number of numerical simulations and actual measurements.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.7
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• pp.32-41
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• 1999

In this study, a new knocking control algorithm was developed using the knock threshold value auto-correction algorithm. This algorithm uses the Fast Fourier Transform9FFT) method by measuring cylinder block vibration signals of a 1498 cc four-cylinder spark ignition engine. The experimental results show the proposed knock control algorithm provides improved performance compared to existing methods. The results also show that the proposed FFT algorithm provides real-time adjustment of the knock threshold value.