• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.107-116
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• 2013

We proposed the WSN monitoring system applied the augmented reality to visualize effectively an indoor WSN. To implement system, we used wireless sensor network, indoor location determination, location-based augmented reality technology. First, we composed the wireless sensor networks indoors and implement web server and then get data from server DB using Android phones. Then, we obtained the (x, y) coordinates using the triangulation method from RSSI of three point of the strongest signal strength of the AP's. Also, we adjusted coordinates using the Kalman filter. Finally, we inserted the adjusted coordinates to the latitude and the longitude of the Mixare that use the GPS signal, and we got location of user and wireless sensor in the server DB. After that, we implemented augmented reality system using the android phone and wireless sensor location and data and real life image.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.2
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• pp.108-117
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• 2009

The South Korean government is looking for a solution to the ever-growing problems of traffic congestion, and surging international oil prices: the use of the humble bicycle to get to places. However, Many people feel inconvenient using bicycle because of the insufficient bicycle infrastructure and lack of the safety and connectivity between existing pathways. In this study, bicycle level of service model using ordered probit model is developed considering safety, convenience, connectivity, and factors that affect bicycle LOS. The ordered probit model would be recommended for the research which relates in choice, preference and strength etc. Bicycle level of service criteria is calculated by applying this model reflecting bicyclist's point of view. The model which develops from this research which accomplishes a bicycle level of service evaluation and represent alternative solution to encourage bicyclist. It is believed that the proposed model would be greatly utilized in bicycle network planning, bicycle road and facility alternatives testing, projects funding priority.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.4
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• pp.116-125
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• 2020

Incalculable damage will be incurred if the national infrastructure that provides services using GNSS signals is affected by jamming signals. To prevent this, a nationwide GNSS jamming monitoring network is necessary to detect the occurrence of a jamming signal, determine the type, and properly localize the jammer position. In this paper, 2-D images for live GNSS signals were generated to verify the environment of the jamming signals through the presence and type of GNSS jamming signals at K-City, which are the test beds for self-driving vehicles, and Incheon International Airport. The analysis was also conducted to detect the occurrence of the jamming signals, determine the type, and measure the jamming signal strength. As a result, a CWI type of jamming signal was detected in L2 band at K-City and in L5 band at Incheon International Airport.

• Journal of the Korea Society of Computer and Information
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• v.16 no.12
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• pp.11-21
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• 2011

An embedded sensor is significantly influenced by its spatial environment, such as barriers or distance, through low power and signal strength. Due to these causes, noise data frequently occur in an embedded sensor. Because the information acquired from the embedded sensor exists in a time series, it is hard to detect an error which continuously takes place in the time series information on a realtime basis. In this paper, we proposes an error detection method based on time-series prediction that detects error signals of embedded sensors in real time in consideration of the physical characteristics of embedded devices. The error detection method based on time-series prediction proposed in this paper determines errors in generated embedded device signals using a stable distance function. When detecting errors by monitoring signals from an embedded device, the stable distance function can detect error signals effectively by applying error weight to the latest signals. When detecting errors by monitoring signals from an embedded device, the stable distance function can detect error signals effectively by applying error weight to the latest signals.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.1
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• pp.122-130
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• 2012

In this paper, we propose a broadband vehicle antenna that can operate at the WiBro band(2.3~2.4 GHz) for a wireless internet service. The feeding of the proposed antenna consists of two T-matching networks on both side of the polyarcylate substrate, and the two T-matching networks are connected through via holes. The designed antenna was built and installed on a rear window of a commercial sedan, and the antenna performances, such as the reflection coefficients and the radiation gain are measured in the open-sight area. The received signal strength of the designed antenna was also tested in a strong field area as well as in a weak field area. The measurement results show the matching bandwidth($S_{11}$ <10 dB) of about 300 MHz in the WiBro band and the average gain of about -5.13 dBi along the azimuth direction.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.4
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• pp.323-333
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• 2005

Recently the fire is happening at the tunnel and underground - structure internationally. We are socially the economy the actual circumstances which serious loss is happening due to an fire occurrence when fire happened which is closed like tunnel and underground - structure, the collapse from the burglar degradation of strength of tunnel concrete lining and human life damage happen. It causes big problem while the long time disconnects a traffic network. While the fire happened in this research at the tunnel, the paper construct a basis data to deduce the specification regulation about stability of tunnel concrete lining. In this paper, the experiment was carried out for the prevention of explosive spalling of tunnel to use a reinforced Polypropylene concrete which mixes a Polypropylene which are known for the thing by being efficient at a protect of explosive spalling of the concrete. According to the firproof test result of reinforced Polypropylene admixture mortar, Polypropylene admixture of prevention of explosive spalling analyzed 0.2%-0.25%.

• Geomechanics and Engineering
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• v.14 no.1
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• pp.9-17
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• 2018

Brazilian splitting tests, uniaxial compression tests and triaxial compression tests are carried out on the coal samples cored from Shanxi group $II_1$ coal seam of Jiaozuo coal mine, Henan province, China, to obtain their property parameters. Considering the bedding has notable effect on the property parameter of coal, the samples with different bedding angles are prepared. The effects of bedding on the anisotropic characteristics of the coal seam are investigated. A geological geomechanical model is built based on the geology characteristics of the Jiaozuo coal mine target reservoir to study the effects of bedding on the fracture propagations during hydraulic fracturing. The effects of injection pressure, well completion method, in-situ stress difference coefficient, and fracturing fluid displacement on the fracture propagations are investigated. Results show bedding has notable effects on the property parameters of coal, which is the key factor affecting the anisotropy of coal. The hydraulic cracks trends to bifurcate and swerve at the bedding due to its low strength. Induced fractures are produced easily at the locations around the bedding. The bedding is beneficial to form a complicated fracture network. Experimental and numerical simulations can help to understand the effects of bedding on hydraulic fracturing in coalbed methane reservoirs.

• Advances in Computational Design
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• v.3 no.3
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• pp.269-288
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• 2018

180 different 2D numerical analyses have been carried out to estimate the factor of safety (FOS) for rooted slopes. Four different types of vegetated coverage and a variety of slope geometry considering three types of soil have been evaluated in this study. The highly influenced parameters on the slope's FOS are determined. They have been chosen as the input parameters for developing a new practical relationship to estimate the FOS with an emphasis on the roots effects. The dependency of sliding mode and shape considering the soil and roots-type has been evaluated by using the numerical finite element model. It is observed that the inclination and height of the slope and the coverage type are the most important effective factors in FOS. While the soil strength parameters and its physical properties would be considered as the second major group that affects the FOS. Achieved results from the developed relationship have shown the acceptable estimation for the roots slope. The extracted R square from the proposed relationship considering nonlinear estimation has been achieved up to 0.85. As a further cross check, the achieved R square from a multi-layer neural network has also been observed to be around 0.92. The numerical verification considering different scenarios has been done in the current evaluation.

• Structural Engineering and Mechanics
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• v.72 no.6
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• pp.675-687
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• 2019

As the bridges are an integral part of the transportation network, their function as one of the most important vital arteries during an earthquake is fundamental. In a design point of view, the bridges piers, and in particular the wall piers, are considered as effective structural elements in the seismic response of bridge structures due to their cantilever performance. Owing to reduced seismic load during design procedure, the response of these structural components should be ductile. This ductile behavior has a direct and decisive correlation to the development of plastic hinge region at the base of the wall pier. Several international seismic design codes and guidelines have suggested special detailing to assure ductile response in this region. In this paper, the parameters which affect the length of plastic hinge region in the reinforced concrete bridge with wall piers were examined and the sensitivity of these parameters was evaluated on the length of the plastic hinge region. Sensitivity analysis was accomplished by independently variable parameters with one standard deviation away from their means. For this aim, the Monte Carlo simulation, tornado diagram analysis, and first order second moment method were used to determine the uncertainties associated with analysis parameters. The results showed that, among the considered design variables, the aspect ratio of the pier wall (length to width ratio) and axial load level were the most important design parameters in the plastic hinge region, while the yield strength of transverse reinforcements had the least effect on determining the length of this region.

• The Journal of the Korea Contents Association
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• v.11 no.2
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• pp.142-151
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• 2011

All medical information over sensor networks need to transmit and process securely in the u-Health services. The reliability of transmission between u-Health medical sensor devices and gateway is very important issue. When the user moves to other place with u-Health devices, its signal strength is going down and is far from the coverage of gateway. In this case, Malicious user can be carried out an intrusion under the situation. And also rogue gateway can be tried to steal medical information. Therefore, it needs mutual authentication between sensor devices and gateway. In this paper, we design a mutual authentication protocol which divided sessions from an authenticated session are updated periodically. And in order to reduce the traffic overhead for session authentication, we also introduce dynamic session management according to sampling rate of medical sensor type. In order to verify this, we implemented the programs for the test-bed, and got an overall success from three types of experiment.