• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.4
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• pp.1224-1248
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• 2022

In various sensor network applications, such as climate observation organizations, sensor nodes need to collect information from time to time and pass it on to the recipient of information through multiple bounces. According to field tests, this information corresponds to most of the energy use of the sensor hub. Decreasing the measurement of information transmission in sensor networks becomes an important issue.Compression sensing (CS) can reduce the amount of information delivered to the network and reduce traffic load. However, the total number of classification of information delivered using pure CS is still enormous. The hybrid technique for utilizing CS was proposed to diminish the quantity of transmissions in sensor networks.Further the energy productivity is a test task for the sensor nodes. However, in previous studies, a clustering approach using hybrid CS for a sensor network and an explanatory model was used to investigate the relationship between beam size and number of transmissions of hybrid CS technology. It uses efficient data integration techniques for large networks, but leads to clone attacks or attacks. Here, a new algorithm called SBEA (Snowball Endurance Algorithm) was proposed and tested with a bow. Thus, you can extend the battery life of your WSN by running effective copy detection. Often, multiple nodes, called observers, are selected to verify the reliability of the nodes within the network. Personal data from the source centre (e.g. personality and geographical data) is provided to the observer at the optional witness stage. The trust and reputation system is used to find the reliability of data aggregation across the cluster head and cluster nodes. It is also possible to obtain a mechanism to perform sleep and standby procedures to improve the life of the sensor node. The sniffers have been implemented to monitor the energy of the sensor nodes periodically in the sink. The proposed algorithm SBEA (Snowball Endurance Algorithm) is a combination of ERCD protocol and a combined mobility and routing algorithm that can identify the cluster head and adjacent cluster head nodes.This algorithm is used to yield the network life time and the performance of the sensor nodes can be increased.

• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.3080-3087
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• 2023

Thermoelectric (TE) materials working in radioisotope thermoelectric generators are irradiated by neutrons throughout its service; thus, investigating the neutron irradiation stability of TE devices is necessary. Herein, the influence of neutron irradiation with fluences of 4.56 × 10¹⁰ and 1 × 10¹³ n/cm² by pulsed neutron reactor on the electrical and thermal transport properties of n-type Bi₂Te_2.7Se_0.3 and p-type Bi_0.5Sb_1.5Te₃ thermoelectric alloys prepared by cold-pressing and molding is investigated. After neutron irradiation, the properties of thermoelectric materials fluctuate, which is related to the material type and irradiation fluence. Different from p-type thermoelectric materials, neutron irradiation has a positive effect on n-type Bi₂Te_2.7Se_0.3 materials. This result might be due to the increase of carrier mobility and the optimization of electrical conductivity. Afterward, the effects of p-type and n-type TE devices with different treatments on the output performance of TE devices are further discussed. The positive and negative effects caused by irradiation can cancel each other to a certain extent. For TE devices paired with p-type Bi_0.5Sb_1.5Te₃ and n-type Bi₂Te_2.7Se_0.3 thermoelectric legs, the generated power and conversion efficiency are stable after neutron irradiation.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.374-381
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• 2023

This study focuses on the implementation of C-band radio navigation in the 5.03 ~ 5.15 GHz terrestrial band to cooperate with GNSS navigation mainly used in existing UAMs. This is one of the navigation technologies that can fully satisfy the requirements of Title 14 of CFR-135.165. According to the FAA, the use of two or more independent navigation sources for aircraft is proposed for aircraft. This study proceeded with the link budget derivation through radio wave propagation path loss analysis, and antenna shape design for miniaturized Doppler VOR, and DME design with enhanced positional distance resolution compared to conventional aircraft. The ground navigation system which is the result of this study, consists of a VOR/DME ground station and a terminal that can be mounted on UAM. Significant performance was confirmed through the production and testing of each prototype.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.436-446
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• 2023

In the field of safety-critical systems, analyzing the effects of various failure factors (failure modes) is essential through Failure Mode and Effects Analysis (FMEA). However, with the increasing importance of software in systems, applying FMEA analysis to the design phase has become challenging. This paper proposes the use of Automatic FMEA, which can automatically perform FMEA using model-based design techniques, and presents a case study of FMEA for automotive engines. A comparison is made between the model-based Automatic FMEA analysis tool and existing FMEA tools. The study aims to demonstrate the performance of the Automatic FMEA analysis tool and propose future research plans.

• Composites Research
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• v.20 no.3
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• pp.17-24
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• 2007

In this study, the failure modes by ballistic impacts were studied both for a neat Kevlar woven fabric and a Kevlar liquid armor impregnated with shear thickening fluid (STF) containing silica particles. These two materials showed quite different failure modes macroscopically in ballistic impacts tests used by Cal.22 FSP and 9mm FMJ bullet. Yarn pull-out for the neat Kevlar woven fabric and yarn fracture occurred partially through all plies from 1st ply to last one for the STF-Kevlar are an important energy absorption mechanisms. The results observed by S.E.M showed commonly fiber damage which are torn skin in the longitudinal fiber direction, fiber split axially and fiber fracture for two materials. The reasons why STF-kevlar liquid armor material exhibits excellent ballistic performance are as follow: firstly the increased friction forces between yarn-yarn and fabric-fabric covered with silica particles and secondary the evolution of shear thickening phenomenmon resulting in suppression of yarn mobility.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.3
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• pp.65-70
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• 2023

In recent years, the digital media environment has begun to diversify, with a greater focus being placed on user-centric design. With the development of digital technology, the digital media environment has formed a vast network of information, which supports interactive communication between people, creating a need for user-centric research. Mobile displays, as a representation of the digital media environment, have the advantage of mobility through the use of thin screen displays and low-performance image sensors, which allow for miniaturization and power saving. However, this results in reduced colour accuracy compared to large displays. This study investigates users' colour perception when using dark and light mode mobile displays. Colour perception was measured using a psycho-physical experiment, which controls each colour attribute based on the 12 colours of KS. The results were analysed to determine whether there is a difference in colour perception between dark mode and light mode, and if the difference was statistically significant. Future research directions based on the results are then discussed.

• Journal of Ceramic Processing Research
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• v.13 no.spc2
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• pp.260-264
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• 2012

We have investigated the effect of ambient gases on the structural, electrical, and optical characteristics of IZO thin films intended for use as anode contacts in the organic light emitting diodes (OLED) devices. These IZO thin films were deposited on the PES film by radio frequency (RF) magnetron sputtering under different ambient gases (Ar, Ar + O2, and Ar + H2) at room temperature. In order to investigate the influences of the ambient gases, the flow rate of oxygen and hydrogen in argon has been changed from 0.1 sccm to 0.5 sccm, respectively. All the IZO thin film has an (222) preferential orientation regardless of ambient gases. The electrical resistivity of the IZO film increased with increasing O2 flow rate, whereas the electrical resistivity decreased sharply under an Ar + H2 atmosphere and was nearly similar regardless of the H2 flow rate. The change of electrical resistivity with changes in the ambient gas composition was mainly interpreted in terms of the charge carrier concentration rather than the charge carrier mobility. All the films showed the average transmittance over 85% in the visible range. The OLED device was fabricated with different IZO substrates made with the configuration of IZO/α-NPD/DPVB/Alq3/LiF/Al in order to elucidate the performance of the IZO substrate. The current density and the luminance of OLED devices with IZO thin films deposited in 0.5 sccm H2 ambient gas are the highest amongst all other films.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.7
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• pp.759-768
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• 2018

As the number of exchange in various fields between countries increases, the number of international conference increases. Many students study simultaneous interpretation due to the increased demand of simultaneous interpretation. Since simultaneous interpretation requires a lot of learning time, students majoring in translation perform the self learning. The paper based sight translation training system is a representative self learning method, but backtracking decreases the efficiency of self learning and it requires the help of the partner. To improve the learning efficiency, computer based sight translation training system has been proposed. However, since students uses the computer based sight translation training system only in a fixed area due to low mobility of computer, the utilization of the system decreases. In this paper, smart device based sight translation training system has been proposed to increase the utilization of the proposed system. Since smart device has lower computing capabilities than the computer, we have proposed algorithms to deal with the low performance. We implement and evaluate the functionalities of the proposed training system.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.5
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• pp.237-242
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• 2023

Research on high-performance walking robots is being actively conducted, and quadruped walking robots are receiving a lot of attention due to their excellent mobility and adaptability on uneven terrain, but they are difficult to introduce and utilize due to high cost. In this paper, to increase utilization by applying intelligent functions to a low-cost quadruped robot, we present a method of improving uneven terrain overcoming ability by mounting IMU and reinforcement learning on embedded board and automatically detecting objects using camera and deep learning. The robot consists of the legs of a quadruped mammal, and each leg has three degrees of freedom. We train complex terrain in simulation environments with designed 3D model and apply it to real robot. Through the application of this research method, it was confirmed that there was no significant difference in walking ability between flat and non-flat terrain, and the behavior of performing person detection in real time under limited experimental conditions was confirmed.

• Korean Journal of Materials Research
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• v.33 no.9
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• pp.372-376
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• 2023

Transparent conductive tungsten (W) doped indium oxide (In₂O₃; IWO) films were deposited at different substrate bias voltage (-V_b) conditions at room temperature on glass substrates by radio frequency (RF) magnetron sputtering and the influence of the substrate bias voltage on the optical and electrical properties was investigated. As the substrate bias voltage increased to -350 V_b, the IWO films showed a lower resistivity of 2.06 × 10^-4 Ωcm. The lowest resistivity observed for the film deposited at -350 V_b could be attributed to its higher mobility, of 31.8 cm²/Vs compared with that (6.2 cm²/Vs) of the films deposited without a substrate bias voltage (0 V_b). The highest visible transmittance of 84.1 % was also observed for the films deposited at the -350 V_b condition. The X-ray diffraction observation indicated the IWO films deposited without substrate bias voltage were amorphous phase without any diffraction peaks, while the films deposited with bias voltage were polycrystalline with a low In₂O₃ (222) diffraction peak and relatively high intensity (431) and (046) diffraction peaks. From the observed visible transmittance and electrical properties, it is concluded that the opto-electrical performance of the polycrystalline IWO film deposited by RF magnetron sputtering can be enhanced with effective substrate bias voltage conditions.