• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.11
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• pp.2736-2744
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• 2013

In this paper, we present a Smart Water Treatment Plant using Zigbee USN devices and a real-time monitoring system in K-water Flow Meter Calibration Center Building. For verification, the data of vertical type WTP such as flow rate, pressure, water level and water temperature are obtained by the Zigbee USN devices, operating in 2.45 GHz band, and be wirelessly surveilled by the real-time monitoring system. The received data from the sensor is transmitted to the data processing device, and then the processed data can be monitored on a smart phone. Consequently, the pilot plant based on the low-cost and high-efficiency USN has been developed with the performance analysis for the communication network and remote monitoring system on mobile devices.

• Journal of Platform Technology
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• v.6 no.2
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• pp.3-9
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• 2018

Recently VR environment is used in many areas including mobile learning, smart factory. However HMD(head-mounted display) is required to a dedicated and expensive system with high-end specification. When designing a VR system, it is needed to handle performance, mobility and usability. Many VR applications need to handle diverse sensors and user inputs continuously in a streaming manner. In this paper we design a VR mobile platform and implement a low-cost mobile VR HMD running on the platform. The VR HMD supports 3D contents delivery in a mobile manner. It is used to detect the motion detection based on angle value of a VR player from accelerator and gyro sensor. The MPU-6050, 6-axis sensor, is used to get a sensory value and the sensory value is taken as an input to a VR rendering server on a Unity game engine that is generated 3D images.

• Korean Journal of Materials Research
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• v.22 no.11
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• pp.609-614
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• 2012

We report on the NO gas sensing properties of non-directional ZnO nanofibers synthesized using a typical electrospinning technique. These non-directional ZnO nanofibers were electrospun on an $SiO_2$/Si substrate from a solution containing poly vinyl alcohol (PVA) and zinc nitrate hexahydrate dissolved in distilled water. Calcination processing of the ZnO/PVA composite nanofibers resulted in a random network of polycrystalline ZnO nanofibers of 50 nm to 100 nm in diameter. The diameter of the nanofibers was found to depend primarily on the solution viscosity; a proper viscosity was maintained by adding PVA to fabricate uniform ZnO nanofibers. Microstructural measurements using scanning electron microscopy revealed that our synthesized ZnO nanofibers after calcination had coarser surface morphology than those before calcination, indicating that the calcination processing was sufficient to remove organic contents. From the gas sensing response measurements for various NO gas concentrations in dry air at several working temperatures, it was found that gas sensors based on electrospun ZnO nanofibers showed quite good responses, exhibiting a maximum sensitivity to NO gas in dry air at an operating temperature of $200^{\circ}C$. In particular, the non-directional electrospun ZnO nanofiber gas sensors were found to have a good NO gas detection limit of sub-ppm levels in dry air. These results illustrate that non-directional electrospun ZnO nanofibers are promising for use in low-cost, high-performance practical NO gas sensors.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.11
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• pp.865-871
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• 2017

In this paper, a gelatin layer was formed on the surface of the twisted fiber-optic couplers fabricated by hydrofluoric acid, which can be used to measure relative humidity. The proposed method of sensors has advantage of low cost compared with the sensors based on the conventional electronic devices and takes beneficial characteristics of optical fibers and light. The fiber-optic sensors presented in this study show a measurement from about 40% to 85% relative humidity, and the experimental results agree well with the calculated results. Based on the design presented in this paper, the structure will enable promising applications in the detecting humidity and various hazardous gases.

• Korean Journal of Remote Sensing
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• v.24 no.2
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• pp.153-164
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• 2008

According to the economic growth, many highways are constructed for increasing need of better life style. Especially roads and roadside facilities are used for accident prevention and offering mobility for drivers. For these purpose, roads and roadside facilities should be well maintained and managed. Now, many roads and roadside facilities are constructed in many areas. Because of traditional surveying method requires much time and surveying efforts, we designed and developed mobile mapping system for highway maintenance and management purpose using multi sensors. We tested our mobile mapping system and data management process. Using developed database, road managers can easily check the information of facility conditions, positions, and attributes. We are expecting low cost and efficient road maintenance process by using our system.

• Smart Structures and Systems
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• v.2 no.2
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• pp.115-126
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• 2006

The Terra-Scope system is an affordable 4-D down-hole seismic monitoring system based on independent, microprocessor-controlled sensor Pods. The Pods are nominally 50 mm in diameter, and about 120 mm long. They are expected to cost approximately $6000 each. An internal 16-bit, extremely low power MCU controls all aspects of instrumentation, eight programmable gain amplifiers, and local signal storage. Each Pod measures 3-D acceleration, tilt, azimuth, temperature, and other parametric variables such as pore water pressure and pH. Each Pod communicates over a standard digital bus (RS-485) through a completely web-based GUI interface, and has a power consumption of less than 400 mW. Three-dimensional acceleration is measured by pure digital force-balance MEMS-based accelerometers. These accelerometers have a dynamic range of more than 115 dB and a frequency response from DC to 1000 Hz with a noise floor of less than $30ng_{rms}/{\surd}Hz$. Accelerations above 0.2 g are measured by a second set of MEMS-based accelerometers, giving a full 160 dB dynamic range. This paper describes the system design and the cooperative shared-time scheduler implemented for this project. Restraints accounted for include multiple data streams, integration of multiple free agents, interaction with the asynchronous world, and hardened time stamping of accelerometer data. The prototype of the device is currently undergoing evaluation. The first array will be installed in the spring of 2006.

• Journal of the Korea Society of Computer and Information
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• v.18 no.8
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• pp.113-119
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• 2013

The requirement of rehabilitation is increasing from the stroke, spinal cord injury. One of the most difficult part is the upper limb rehabilitation because of its nervous complexity. A rehabilitation has effectiveness when a professional therapist treats in work at facility, but it has problems of an accessibility, a constant availability, a self-participation and taking lots of cost and time. In this paper, we test and experiment the accuracy and execution time of the pattern recognition algorithms like PCA, ICA, LDA, SVM to show the recognition possibility of it on the upper limb function from the 3D trajectory information which is gathered from stereo vision sensor(Kinect). From the result, PCA, ICA have low accuracy, but LDA, SVM have good accuracy to use for physical rehabilitation on the upper limb function.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.6
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• pp.1113-1122
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• 2020

Recently, as violent crimes of crime without reason (Korea : Do not ask), women and the elderly are getting serious. In the existing system, many CCTVs are installed, but it is difficult to prevent crime due to only follow-up measures after a crime occurs. This device prevents crime through this device for incidents in shaded areas and closed spaces such as apartments and buildings. To do this, we research this technology to develop products and software. It sends an alarm signal using communication technology to a specific place where you want to receive an event of an alarm or a CCTV device operated using image analysis big data technology and convergence sensor technology for a specific target of the behavior expected to be a crime or movement. Develop the device. This development device researches and develops this device and supplies low-cost devices to consumers, which is used as a device that predicts the occurrence of crime in advance, processes it as an alarm signal in real time, and transmits it, and constitutes a standalone device and a server. Will provide the device to be connected.

• Journal of IKEEE
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• v.26 no.2
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• pp.219-225
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• 2022

The textile industry in Korea, the dyeing sector is an energy-intensive sector and has low per-unit productivity due to its labor-intensive nature. If the defective rate of dyed fabrics is high, additional costs are incurred due to an increase in production cost due to re-dyeing. Therefore, the goal of the dyeing factory was to minimize the defect rate rather than to save energy. It was difficult to check the dyeing state of the fabric in real time due to the risk of accidents due to burns or pressure when dyeing in a high-temperature and high-pressure environment. In this paper, a complex sensor that can measure the exhaustion rate of dye solution in the dyeing machine using turbidity, pH, and conductivity sensors was proposed, and the experimental method and experimental results were analyzed.

• Journal of Sensor Science and Technology
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• v.32 no.3
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• pp.174-179
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• 2023

Bulk trailers, used for the transportation of powdered materials, such as cement and fly ash, are crucial in the construction industry. The speedy exhaustion of powdered materials stored in the tank of bulk trailers is relevant to improving transportation efficiency and reducing transportation costs. The exhaust time can be reduced by developing an automatic control system to replace the manual exhaust operation. The instantaneous or accumulated exhausts of powdered materials must be measured for automatic control of the bulk trailer exhaust system. Accordingly, we previously proposed a recurrent neural network (RNN) model that estimated the instantaneous exhaust based on low-cost pressure sensor signals without an expensive flowmeter for powders. Although our previous study utilized only an RNN model, models such as multilayer perceptron (MLP) and convolutional neural network (CNN) are also widely utilized for time-series estimation. This study compares the performance of three neural network models (MLP, CNN, and RNN) in estimating instantaneous and accumulated exhausts. In terms of the instantaneous exhaust estimation, the difference in the performance of neural network models was insignificant (that is, 8.64, 8.62, and 8.56% for the MLP, CNN, and RNN, respectively, in terms of the normalized root mean squared error). However, in the case of the accumulated exhaust, the performance was excellent in the order of CNN (1.67%), MLP (2.03%), and RNN (2.20%).