• The Journal of the Korea Contents Association
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• v.20 no.9
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• pp.249-260
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• 2020

This research examined Israel's economic trends, trades, and cooperation with Korea prior to the entry into force of the Free Trade Agreement (FTA) between Korea and Israel. Also, this research assessed opportunities and ways to expand the above more easily. Israel has a high level of technology in basic materials and information technology (IT). Meanwhile, Korea mainly exports automobiles and wireless communication equipment to Israel and imports semiconductor-related equipment and aviation components from Israel. Moreover, since the two countries signed a trade agreement in August 2019, they expect to expand trade with each other. As such, in order to promote multilateral trade and cooperation between the two countries, it is necessary to expand joint development opportunities through mutual collaboration on basic industries and smart mobility that Korea is in need. Further, Korean construction and materials companies related to the SOC industry in Israel should accelerate their local advances. In addition, more of the governmental support should be provided to foster regional experts and to offer various information to the companies entering the country.

• Korean Journal of Materials Research
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• v.31 no.7
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• pp.392-396
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• 2021

Expensive PCBN or ceramic cutting tools are used for processing of difficult-to-cut materials such as Ti and Ni alloy materials. These tools have the problem of breaking easily due to their high hardness but low fracture toughness. To solve these problems, cutting tools that form various coating layers are used in low-cost WC-Co hard material tools, and research on various tool materials is being conducted. In this study, binderless-WC, WC-6 wt%Co, WC-6 wt%Co-1 wt% Mo₂C, and WC-6 wt%Co-2.5 wt% Mo₂C hard materials are densified using horizontal ball milled WC-Co, WC-Co-Mo₂C powders, and spark plasma sintering process (SPS process). Each SPSed Binderless-WC, WC-6 wt%Co-1 wt% Mo₂C, and WC-6 wt%Co-2.5 wt% Mo₂C hard materials are almost completely dense, with relative density of up to 99.5 % after the simultaneous application of pressure of 60 MPa and almost no significant change in grain size. The average grain sizes of WC for Binderless-WC, WC-6 wt%Co-1 wt% Mo₂C, and WC-6 wt%Co-2.5 wt% Mo₂C hard materials are about 0.37, 0.6, 0.54, and 0.43 ㎛, respectively. Mechanical properties, microstructure, and phase analysis of SPSed Binderless-WC, WC-6 wt%Co-1 wt% Mo₂C, and WC-6 wt%Co-2.5 wt% Mo₂C hard materials are investigated.

• Journal of Digital Convergence
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• v.19 no.2
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• pp.425-431
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• 2021

The purpose of this study is to compare and analyze leading brands of the scooter-sharing system market of Korea, KICKGOING and Lime, in terms of user experience, and to suggest the improvement direction of the applications and scooters of those two services. The assessment was conducted in such a way that the experimental group using scooter-sharing system over a certain frequency would choose the specific service they use most frequently, and complete a questionnaire: based on the reorganized version of the Peter Morville's Honeycomb Model. Based on the results of the experiment, We drew a conclusion that the services need to add navigation features in the application, to provide more simple procedures for reporting breakdown or accident and browsing insurance information, and to improve the user and pedestrian safety levels by gamification, et cetera. We expect this study to help the fast-growing smart mobility market and scooter-sharing systems that represent the market develop into a user-centered way.

• Journal of IKEEE
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• v.25 no.4
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• pp.634-643
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• 2021

In this paper, an FPGA-based acceleration scheme of range Doppler algorithm (RDA) is proposed for the real time synthetic aperture radar (SAR) imaging. Hardware architectures of matched filter based on systolic array architecture and a high speed sinc interpolator to compensate range cell migration (RCM) are presented. In addition, the proposed hardware was implemented and accelerated on Xilinx Alveo FPGA. Experimental results for 4096×4096-size SAR imaging showed that FPGA-based implementation achieves 2 times acceleration compared to GPU-based design. It was also confirmed the proposed design can be implemented with 60,247 CLB LUTs, 103,728 CLB registers, 20 block RAM tiles and 592 DPSs at the operating frequency of 312 MHz.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.9
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• pp.289-304
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• 2022

It is necessary to apply process algebra and logic in order to analyze and verify safety requirements for Smart IoT Systems due to distributivity and mobility of the systems over some predefined geo-temporal space. However the analysis and verification cannot be fully intuitive over the space due to the fact that the existing process algebra and logic are very limited to express the distributivity and the mobility. In order to overcome the limitations, the paper presents a new logic, namely for GTS-VL (Geo-Temporal Space-Visual Logic), visualization of the analysis and verification over the space. GTS-VL is the first order logic that deals with relations among the different types of blocks over the space, which is the graph that visualizes the system behaviors specified with the existing dTP-Calculus. A tool, called SAVE, was developed over the ADOxx Meta-Modeling Platform in order to demonstrate the feasibility of the approach, and the advantages and practicality of the approach was shown with the comparative analysis of PBC (Producer-Buffer-Consumer) example between the graphical analysis and verification method over the textual method with SAVE tool.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.3
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• pp.271-280
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• 2023

Pedestrian Dead Reckoning (PDR) methods using initial sensors are being studied to provide the location information of smart device users in indoor environments where satellite signals are not available. PDR can continuously estimate the location of a pedestrian regardless of the walking environment, but has the disadvantage of accumulating errors over time. Unlike this, WiFi signal-based wireless positioning technology does not accumulate errors over time, but can provide positioning information only where infrastructure is installed. It also shows different positioning performance depending on the environment. In this paper, an integrated positioning technology integrating two positioning techniques with different error characteristics is proposed. A technique for correcting the error of PDR was designed by using the location information obtained through WiFi Measurement-based fingerprinting as the measurement of Extended Kalman Filte (EKF). Here, a technique is used to variably calculate the error covariance of the filter measurements using the WiFi Fingerprinting DB and apply it to the filter. The performance of the proposed positioning technology is verified through an experiment. The error characteristics of the PDR and WiFi Fingerprinting techniques are analyzed through the experimental results. In addition, it is confirmed that the PDR error is effectively compensated by adaptively utilizing the WiFi signal to the environment through the EKF to which the adaptive error covariance proposed in this paper is applied.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.812-816
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• 2007

Having been speedy development of the IT industry, devices such as set-top box and smart phone are used in the broad filed. Because Java has merits that are platform independency, security and mobility, that is important software platform to offer stable services in the small device. This needs JVM(Java Virtual Machine) to execute Java application in the small device. CVM(Classic Virtual Machine) which is the kind of JVM is designed for embedded device to have limited resources. In this paper, CVM which is defined by CDC has designed and implemented on the Real-Time Operating System, UbiFOS$^{TM}$.

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.3
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• pp.142-152
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• 2014

Vehicular Ad-hoc Networks (VANETs) are comprised of wireless mobile nodes characterized by a randomly changing topology, high mobility, availability of geographic position, and fewer power constraints. Orthogonal Frequency Division Multiplexing (OFDM) is a promising candidate for the physical layer of VANET because of the inherent characteristics of the spectral efficiency and robustness to channel impairments. The susceptibility of OFDM to Inter-Carrier Interference (ICI) is a challenging issue. The high mobility of nodes in VANET causes higher Doppler shifts, which results in ICI in the OFDM system. In this paper, a frequency domain com-btype channel estimation was used to cancel out ICI. The channel frequency response at the pilot tones was estimated using a Least Square (LS) estimator. An efficient interpolation technique is required to estimate the channel at the data tones with low interpolation error. This paper proposes a robust interpolation technique to estimate the channel frequency response at the data subcarriers. The channel induced noise tended to degrade the Bit Error Rate (BER) performance of the system. Parallel concatenated Convolutional codes were used for error correction. At the decoding end, different decoding algorithms were considered for the component decoders of the iterative Turbo decoder. A performance and complexity comparison among the various decoding algorithms was also carried out.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.01a
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• pp.281-282
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• 2022

현재 전동 킥보드 헬멧 미착용으로 인한 사고가 끊임없이 야기되고 있다. 개인형 이동장치 이용자 수가 증가함에 따라 법 개정을 통하여 헬멧 착용이 의무 사항이지만 여전히 낮은 착용률을 나타내고 있다. 본 논문에서는 모든 공유 킥보드 회사에서 사용 가능한 딥러닝 기반의 전동킥보드 헬멧 착용 인식시스템을 제시한다. 타 공유 전동킥보드 회사 앱에서 본 논문의 결과물을 사용할 때는 사용자가 타사 앱에서 헬멧 인식 요청 시 자사 앱에서 헬멧 착용 여부를 인식하여 결과를 전송한다. 자사 앱 사용자는 인식 기록을 조회할 수 있고, 타사 관리자는 사용자의 정보를 조회 및 관리할 수 있다. 본 시스템을 통해 전동킥보드 이용 시 헬멧 착용을 장려하여 착용률 증가와 사고 시 인명피해 감소를 기대한다.