• Journal of the Korea Society of Computer and Information
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• v.22 no.9
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• pp.107-113
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• 2017

In this paper, we propose a medication reminder system using IoT platforms and products to help old adults keep track of their medication schedule, one of 10 Korean instrumental activities in daily living (K-IADL). An interworking architecture based on the oneM2M standard platform is designed to allow various IoT products to be connected each other through interworking proxy entities. A prototype system for the medication reminder service is developed, which consists of a pair of off-the-shelf pill bottle and container box embedded with an NFC tag and reader respectively, three types of actuators including a LIFX LED lightbulb, Musaic speaker, Microsoft Band 2, and smartphone applications. The experiment shows that our medication reminder system can make alarms for old adults to take their pills appropriately considering where they are and when they have food inferred from data collected from sensors including ultrasonic sensor and rice cooker, fostering them to keep their medication routine.

• Journal of Sensor Science and Technology
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• v.26 no.1
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• pp.60-65
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• 2017

This paper describes the low noise and low power IC using the opamp sharing technique for the capacitive micro-sensor sensing platform. The proposed IC reduces noise using correlated double sampling (CDS) and reduces power consumption using the opamp sharing technique. The IC is designed to be fully programmable, and can be digitally controlled by serial peripheral interface (SPI). The power consumption and the integrated input referred noise are 1.02 mW from a 3.3 V supply voltage and $0.164aF_{RMS}$ with a bandwidth of 400 Hz. The capacitive sensitivity, the input-output linearity and the figure of merits (FoM) are 2.5 mV/fF, 2.46 %FSO, and 8.4, respectively.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.4
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• pp.374-383
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• 2012

In this study, we have observed the airborne radon levels in the subway cabins before and after platform screen doors (PSD) installation. The measurements have been conducted at Seoul metropolitan subway lines in 2008, 2009 and 2010. The mean concentration of the radon inside subway cabins were increased by approximately 53% from $20.1Bq/m^3$ to $30.8Bq/m^3$ by installing PSD. After PSD installation, measured values for the different lines were rather different, and varied between 8.2 and $76.5Bq/m^3$. And mean radon concentrations were in the decreasing order for subway lines 5, 6, 7, 8, 3, 4, 2, 9 and 1. It was also found that the indoor radon concentrations in the subway cabins were highly dependent on the management approach of a ventilation system at the subway stations. By assuming an average of $720\;h\;year^{-1}$ and $2,880\;h\;year^{-1}$ spent in subway cabin, effective doses to passengers and employee were estimated. The expected annual effective dose, in case of an equilibrium factor of 0.4, were $0.07mSv\;y^{-1}$ and $0.26mSv\;y^{-1}$, respectively.

• Korean Journal of Remote Sensing
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• v.36 no.2_2
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• pp.263-275
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• 2020

In this study, DEMs (Digital elevation model) based on LIDAR, TanDEM-X and UAV (Unmanned Aerial Vehicle) are used to analyze topographic change of Gomso tidal flat during a few years. DEM from LIDAR data was observed at 2011 by KHOA (Korean hydrographic and oceanographic agency) and DEM based on TanDEM-X data was generated at Lee and Ryu (2017). UAV data was observed at KM and KH area of Gomso tidal flat. KM area was surveyed at MAY and AUG 2019, and KH area was surveyed at APR 2018 and MAY 2019. During research period, 2011 to AUG 2019, elevation of KM area is decreased 0.24 m in average, and Chenier is retreat to landward about 130 m. In KH area, elevation is increased 0.16 m in average during research period, 2011 to MAY 2019. It is expected that multi-platform remotely sensed data can help to study accurate topographic change of tidal flat.

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.7
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• pp.183-194
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• 2018

With the rapid development of IoT(Internet of Things) technology, various convenient services such as smart home and smart city have been realized. However, IoT devices in unmanned environments are exposed to various security threats including eavesdropping and data forgery, information leakage due to unauthorized access. To build a secure IoT environment, it is necessary to use proper cryptographic technologies to IoT devices. But, it is impossible to apply the technologies applied in the existing IT environment, due to the limited resources of the IoT devices. In this paper, we survey the classification of IoT devices according to the performance and analyze the security requirements for IoT devices. Also we survey and analyze the use of cryptographic technologies in the current status of IoT open standard platform such as AllJoyn, oneM2M, IoTivity. Based on the research of cryptographic usage, we examine whether each platform satisfies security requirements. Each IoT open platform provides cryptographic technology for supporting security services such as confidentiality, integrity, authentication an authorization. However, resource constrained IoT devices such as blood pressure monitoring sensors are difficult to apply existing cryptographic techniques. Thus, it is necessary to study cryptographic technologies for power-limited and resource constrained IoT devices in unattended environments.

• Journal of Multimedia Information System
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• v.3 no.3
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• pp.85-90
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• 2016

We firstly tried to understand consumers' purchasing tendencies and mainly focused on designing a platform model that offers integrated support. C2B (Customer to Business) orders integrate with a consumption platform of a B2C (Business to Customer) model, and integrated support aims at design, supply, processing, and distribution of a fashion business. All the information such as orders, sales, production, supply, and settlement of accounts is synchronized under the C2B, B2C, and O2O (Online to Offline) environment so that accurate information can be shared in real time. Our platform automatically handles with a net income of a product designer, manufacturer, and shipping company once shipping is confirmed.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.1
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• pp.59-67
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• 2012

Platform screen doors (PSD) installed at 289 stations in Seoul metropolitan subway from November 2005 to December 2009, are expected to prevent death from a fall and improve air quality. In this study, we systematically surveyed changes in radon concentrations before and after PSD installation in Seoul metropolitan subway stations. By solid-state nuclear track detectors (SSNTD), the radon concentrations before and after the PSD installation were measured at 54 stations of 6 lines from 2 to 7 reported to have relatively high radon concentrations. Mean radon concentrations at platforms were decreased by approximately 56% from 121.7 Bq/$m^3$ to 54.0 Bq/$m^3$. Before PSD installation, mean radon concentrations were in the decreasing order for subway lines 7, 5, 6, 3, 4 and 2. On the other hand, after PSD installation the order was changed to 5, 6, 7, 3, 4 and 2. According to a radon map of Seoul metropolitan subway, the number of platforms where radon concentration over was 74 Bq/$m^3$ decreased from 38 to 12 after PSD installation.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.5
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• pp.669-674
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• 2016

The purpose of this study is to demonstrate the suitability of hydrogen peroxide($H_2O_2$) vapor system for platform interior decontamination. Geobacillus stearothermophilus biological indicator(BI) strips and a field tent were used as a biological simulant and as a simulated platform, respectively. Decontamination was performed based on injection rates and tent sizes with exposure time 60 minutes. We standardized the conditions for the field tent decontamination : 8.0 g/min for $30m^3$($H_2O_2$ vapor concentration of 150~500 ppm, relative humidity of 50 %) and 12.0 g/min for $60m^3$($H_2O_2$ vapor concentration of 250~400 ppm, relative humidity of 55 %). Thus we suggest the system is one of the possible candidates for decontamination of platform interiors.

• Korean Journal of Food Science and Technology
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• v.46 no.4
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• pp.522-525
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• 2014

The effects of temperature and inosine monophosphate (IMP) on the germination of artificially inoculated Bacillus cereus spores in ganjang, doenjang, and gochujang sauces were investigated. The pH and salt concentration of the sauces were as follows: ganjang (4.84, 7.45%), doenjang (4.26, 5.07%), and gochujang (3.54, 3.24%), respectively. Treatment at $40^{\circ}C$ or $80^{\circ}C$ resulted in a B. cereus growth of 0.8 log CFU/g in ganjang sauce; this concentration increased to 2.25 log CFU/g and 1.21 log CFU/g, respectively, when 10 mM IMP was added. Compared with that for ganjang sauce, the germination effect was comparatively lower for doenjang sauce by 10 mM IMP+$40^{\circ}C$ treatment (0.46 log CFU/g) and 10 mM IMP+$80^{\circ}C$ treatment (0.85 log CFU/g). However, no germination effect was noted for gochujang sauce by any treatment in this study. Therefore, the results suggested that pH is an important factor affecting spore germination in sauces.

• Current Applied Physics
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• v.18 no.12
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• pp.1564-1570
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• 2018

Charge transport dynamics in ZnO based inverted organic solar cell (IOSC) has been characterized with transient photocurrent spectroscopy and localised photocurrent mapping-atomic force microscopy. The value of maximum exciton generation rate was found to vary from $2.6{\times}10^{27}m^{-3}s^{-1}$ ($J_{sat}=79.7A\;m^{-2}$) to $2.9{\times}10^{27}m^{-3}s^{-1}$ ($J_{sat}=90.8A\;m^{-2}$) for devices with power conversion efficiency ranging from 2.03 to 2.51%. These results suggest that nanorods served as an excellent electron transporting layer that provides efficient charge transport and enhances IOSC device performance. The photovoltaic performance of OSCs with various growth times of ZnO nanorods have been analysed for a comparison between AM1.5G spectrum and local solar spectrum. The simulated PCE of all devices operating under local spectrum exhibited extensive improvement with the gain of 13.3-3.7% in which the ZnO nanorods grown at 15 min possess the highest PCE under local solar with the value of 2.82%.