• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.2
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• pp.40-45
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• 2007

This study analyzed the resistivity characteristic of model block to make the good use of structure grounding and substitution grounding electrode base of building. After making the model block of mortar and concrete block, it measured resistivity in hydrous condition and dry condition and compared with the blocks that is mixed earth resistance lowering agent to decrease resistivity. The resistance value of block accepted much influence by block resistivity. When the block resistivity was same or similar value, the value of soil resistivity has occurred as different as the value of grounding resistance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.136-140
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• 2015

Linux environment that is commonly used at embedded systems supports various file systems as Ext2, FAT, NTFS, etc. The file system that is equiped on the embedded system is mostly implemented on mini hard disk or flash memory. The types of the file system of the system make an effect on the performance of a application programs. The factors of file system performance on a same media are block read, block write and block free time. On these factors, block read and block free time are not so different according to the type of file systems. This paper evaluates the performance benchmark of file systems supported by linux about block allocation and write performance. The results obtained from various experiments shows the characteristics of each file system.

• Coupled systems mechanics
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• v.8 no.4
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• pp.351-375
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• 2019

The present work investigates the use of a rigid rocking block as a tool to reduce vibrations in a frame structure. The study is based on a simplified model composed by a 2-DOF linear system, meant to represent a general M-DOF frame structure, coupled with a rocking rigid block through a linear visco-elastic device, which connects only the lower part of the 2-DOF system. The possibility to restrain the block directly to the ground, by means of a second visco-elastic device, is investigated as well. The dynamic response of the model under an harmonic base excitation is then analysed in order to evaluate the effectiveness of the coupling in reducing the displacements and the drift of the 2-DOF system. The nonlinear equations of motion of the coupled assemblage 2-DOF-block are obtained by a Lagrangian approach and then numerically integrated considering some reference mechanical and geometrical quantities as variable parameters. It follows an extensive parametric analysis, whose results are summarized through behaviour maps, which portray the ratio between the maximum displacements and drifts of the system, with and without the coupling with the rigid block, for several combinations of system's parameters. When the ratio of the displacements is less than unity, the coupling is considered effective. Results show that the presence of the rocking rigid block improves the dynamics of the system in large ranges of the characterizing parameters.

• International Journal of Highway Engineering
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• v.18 no.6
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• pp.35-40
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• 2016

OBJECTIVES : The objective of this study is to analyze the nonlinear behavior of block pavements using multi-load level falling weight deflectometer (FWD) deflections. METHODS : Recently, block pavements are employed not only in sidewalks, but also in roadways. For the application of block pavements in roadways, the structural capacities of subbase and subgrade are important factors that support the carry traffic load. Multi-load level FWD testing was conducted on block pavements to analyze their nonlinear behavior. The deflection ratio due to the increase in load was analyzed to estimate the nonlinearity of block pavements. Finite element method with nonlinear soil model was applied to simulate the actual nonlinear behavior of the block pavement under different levels of load. RESULTS : The results of the FWD testing show that the center deflections in block pavements are approximately ten times greater than that in asphalt pavements. The deflection ratios of the block pavement due to the increase in the load range from 1.2 to 1.5, indicating that the deflection increased by 20~50%. The material coefficients of the nonlinear soil model were determined by comparing the measured deflections with the predicted deflections using the finite element method. CONCLUSIONS : In this study, the nonlinear behavior of block pavements was reviewed using multi-load level FWD testing. The deflection ratio proposed in this study can estimate the nonlinearity of block pavements. The use of nonlinear soil model in subbase and subgrade increases the accuracy of predicting deflections in finite element method.

• Journal of Korea Multimedia Society
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• v.10 no.7
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• pp.856-868
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• 2007

We propose an effective method for block classification in a document image. The gray level document image is converted to the binary image for a block segmentation. This binary image would be smoothed to find the locations and sizes of each block. And especially during this smoothing, the inner block heights of each block are obtained. The gray level image is divided to several blocks by these location informations. The SGLDM(spatial gray level dependence matrices) are made using the each gray-level document block and the seven second-order statistical texture features are extracted from the (0,1) direction's SGLDM which include the document attributes. Document image blocks are classified to two groups, text and non-text group, by the inner block height of the block at the nearest neighbor rule. The seven texture features(that were extracted from the SGLDM) are used for the five detail categories of small font, large font, table, graphic and photo blocks. These document blocks are available not only for structure analysis of document recognition but also the various applied area.

• Journal of Wetlands Research
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• v.22 no.1
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• pp.1-7
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• 2020

Non-point pollution adversely affects the water system and its influence is increasing. In order to manage such nonpoint source pollution, the government has conducted studies on LID (Low Impact Development) facilities and various efficiency evaluations. In this study, the actual installed permeable block facility among the various LID facilities was analyzed the effluent reduction rate, the residual rainfall analysis, the runoff duration time and the reduction rate of the maximum inflow and outflow for the rainfall runoff control and the results were compared the other facilities. The analysis results show that the reduction efficiency is high in order of impermeable block, filter type permeable block, and clearance type permeable block, and the graph showing the relationship between the rainfall intensity and the runoff duration time is presented. This graph can be helpful in the design of facilities such as the facility capacity selection according to the reproduction period of the permeable block facility similar to this.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.1043-1048
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• 2009

PES (Programmable Electronic System) is used by software development for the train control system. PES has been widely used in real world and consists of hardware, firmware and application software. The PES are easily apply to many applications because its implementation has high flexibility. Many safety critical functions are realized through software in safety critical system. Normally, it is difficult to detect failures for PES system because the PES is too sophisticated to identify sources of the failure. So, the reliability analysis is needed by using software fault tolerance techniques. Currently, there are the recovery block, distributed recovery block, N-version programming, N self-checking programming in fault tolerance techniques. In this paper, the models of recovery block and N-version programming in software fault tolerance techniques are suggested by using the Markov model. Also, the reliability in the train control system is analyzed through changing time. The fault occupancy rates of the program, adjustment test and voter are stationary. So, the relation between time and reliability is presented by using Matlab program. In the result of reliability, the reliability of recovery block is more high than N-version programming in case of the same number of substitution block.

• Journal of IKEEE
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• v.24 no.2
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• pp.378-384
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• 2020

The location information of the people or mover is essential for supporting various smart mobility services in railway stations which are mostly underground. For this purpose, a smart braille block is proposed to identify the location of the mover of the people. In this paper, the frequency characteristics of each material of the upper and lower parts of the braille block are analyzed to examine the appropriate materials for railway history. In addition, the guidelines for actual manufacturing were derived by analyzing the separation distance between two RF sensors in the smart braille block. As a result of analysis through the characteristic analysis in this paper, after selecting the material suitable for the construction site when the smart braille block is applied, the performance change of the RF system, especially the antenna that greatly influences the RF performance, must be reviewed in advance. It seems to have to be applied after checking through.

• The Korean Journal of Pain
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• v.34 no.4
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• pp.509-533
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• 2021

Background: Postherpetic neuralgia (PHN) is a refractory complication of herpes zoster (HZ). To prevent PHN, various strategies have been aggressively adopted. However, the efficacy of these strategies remains controversial. Therefore, we aimed to estimate the relative efficacy of various strategies used in clinical practice for preventing PHN using a network meta-analysis (NMA). Methods: We performed a systematic and comprehensive search to identify all randomized controlled trials. The primary outcome was the incidence of PHN at 3 months after acute HZ. We performed both frequentist and Bayesian NMA and used the surface under the cumulative ranking curve (SUCRA) values to rank the interventions evaluated. Results: In total, 39 studies were included in the systematic review and NMA. According to the SUCRA value, the incidence of PHN was lower in the order of continuous epidural block with local anesthetics and steroids (EPI-LSE), antiviral agents with subcutaneous injection of local anesthetics and steroids (AV + sLS), antiviral agents with intracutaenous injection of local anesthetics and steroids (AV + iLS) at 3 months after acute HZ. EPI-LSE, AV + sLS and AV + iLS were also effective in preventing PHN at 1 month after acute HZ. And paravertebral block combined with antiviral and antiepileptic agents was effective in preventing PHN at 1, 3, and 6 months. Conclusions: The continuous epidural block with local anesthetics and steroid, antiviral agents with intracutaneous or subcutaneous injection of local anesthetics and a steroid, and paravertebral block combined with antiviral and antiepileptic agents are effective in preventing PHN.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.2
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• pp.91-98
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• 1989

The analysis of a single stereo model is not sufficient in applying for some large structures, therefore the precise coordinate analysis photogrammetric block adjustment method should be considered. The distribution of control points has a great influence on the error characteristics of the block adjustment results. Thus, the unit model method is applied to the photogrammentric adjustment procedure to study error characterestics with different distributions of control points. Through this study, the second order polynomial equations about bridging distance and plane error are developed in block adjustment of terrestrial photogrammetry. Comparing the block adjustment method and a single model method, root mean square error of the block adjustment method is 0.44mm, and a single model method is 1.06mm.