• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.25 no.9
• /
• pp.1271-1274
• /
• 2021

RF fingerprinting based on deep learning (DL) has gained interests as a means to improve the security of near field communication (NFC) by allowing identification of NFC tags based on unique physical characteristics. To achieve high accuracy in the identification of NFC tags, it is crucial to utilize a large number of training data, however it is hard to collect such dataset in practice. In this study, we have provided new methodology to generate RF waveform from NFC tags, i.e., data augmentation, based on a conditional generative adversarial network (CGAN). By using the RF waveform of NFC tags which is collected from the testbed with software defined radio (SDR), we have confirmed that the realistic RF waveform can be generated through our proposed scheme.

• Journal of Korea Water Resources Association
• /
• v.54 no.8
• /
• pp.553-566
• /
• 2021

River confluence is often characterized by shear layer and the associated strong mixing. In natural rivers, the main channel and its tributary can be separated by the shear layer using contrasting colors. The shear layer can be easily observed using aerial images from satellite or unmanned aerial vehicles. This study proposes a low-cost identification method extracting geographic features of the shear layer using RGB aerial image. The method consists of three stages. At first, in order to identify the shear layer, it performs image segmentation using a Gaussian mixture model and extracts the water bodies of the main channel and tributary. Next, the self-organizing map simplifies the flow line of the water bodies into the 1-dimensional curve grid. After that, the curvilinear coordinate transformation is performed using the water body pixels and the curve grid. As a result, the shear layer identification method was successfully applied to the confluence between Nakdong River and Nam River to extract geometric shear layer features (confluence angle, upstream- and downstream- channel widths, shear layer length, maximum shear layer thickness).

• Journal of Internet of Things and Convergence
• /
• v.10 no.3
• /
• pp.57-64
• /
• 2024

In this paper, we propose a Line-of-Sight (LoS)/Non-Line-of-Sight (NLoS) identification- based Human Activity Recognition (HAR) system using Channel State Information (CSI) to improve the accuracy of HAR, which dynamically changes depending on the reception environment. to consider the reception environment of HAR system, the proposed system includes three operational phases: Preprocessing phase, Classification phase, and Activity recognition phase. In the preprocessing phase, amplitude is extracted from CSI raw data, and noise in the extracted amplitude is removed. In the Classification phase, the reception environment is categorized into LoS and NLoS. Then, based on the categorized reception environment, the HAR model is determined based on the result of the reception environment categorization. Finally, in the activity recognition phase, human actions are classified into sitting, walking, standing, and absent using the determined HAR model. To demonstrate the superiority of the proposed system, an experimental implementation was performed and the accuracy of the proposed system was compared with that of the existing HAR system. The results showed that the proposed system achieved 16.25% higher accuracy than the existing system.

• Proceedings of the KIEE Conference
• /
• 2002.07b
• /
• pp.1211-1213
• /
• 2002

We have frequently felt it inconvenient to collect fare drawing the card in transportation system. Especially, for subway the fares of mass transportation at rush hours of the days, it's important to find a way to collect fares without unnecessarily delaying passengers. In this paper, we proposed a system for the gateless fare collection passing through the booth in only carrying the card. In this system that RF-ID system and Bluetooth are applied. We designed two wireless communication channels. One is the 125kHz communication channel by FSK and PSK for power supplying on the card and identification and the other is 2.4GHz channel for the collection.

• Proceedings of the Korean Society of Sericultural Science Conference
• /
• 2003.10a
• /
• pp.100-101
• /
• 2003

Gap junctions are membrane channels that directly connect the cytoplasm of neighboring cells, allowing the exchange of ions and small molecules. Two analogous families of proteins, the connexins and innexins are the channel-forming molecular vertebrates and invertebrates, respectively. Here, we present the molecular cloning and sequences analysis of novel innexiins, Binx2, expressed during Bombyx mori embryonic development. (omitted)

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.33B no.3
• /
• pp.133-141
• /
• 1996

As the recording density of digital magnetic recording channels increased, the nonlinear distortion caused by inadequate rise-times, demagnetizing field, and overwrite effect during the recording process becomes significant, resulting in limitation on the recording rate. In this paper, a new method for identifying the nonlinear distortion in hihg-density magnetic recording channel using and i.i.d. (independent, identically distributed) inut is described. The proposed method does not require the operatin of large-size matrix inversion which are necessary for the conventional method, and it enables us to estimate nonlinear parameters transition shifts, which can be used to compensate the nonlinear distortion, is demonstrated by computer simulations.

• Proceedings of the IEEK Conference
• /
• 2002.06b
• /
• pp.205-208
• /
• 2002

An existing ATM switch fabric uses VPI(Virtual Path Identifier) and VCI(Virtual Channel Identifier) information to route ATM cell. But AAL type 2 switch which efficiently processes delay-sensitive, low bit-rate data such as a voice routes the ATM cell by using CID(Channel Identification) field in addition to VPI and VCI. In this paper, we research the AAL type 2 switch that performs the process of CPS packet. The Receive unit extracts the CPS packet from the inputted ATM cell. The designed receive unit consists of input FIFO, r)( status table, CAM(Content Addressable Memory), new CID table and partial packet memory. Also the designed receive unit supports the PCI interface with host processor. The receive unit is implemented in Xilinx FPGA and operates at 72MHz.

• Proceedings of the Safety Management and Science Conference
• /
• 2008.04a
• /
• pp.361-366
• /
• 2008

본 연구는 최근 산업 전반에 걸쳐 도입이 확산되고 있는 RFID(Radio Frequency IDentification)기술과 다채널 음성 전달 서비스 기술을 활용하여, 유비쿼터스 환경에서의 SP(Sales Promotion) 광고를 효과적으로 전달하기 위한 새로운 SP광고용 RFID기반의 다채널 음성 안내시스템을 개발함으로서, 향후 RFID/USN시장을 선점할 수 있는 고부가가치의 신규 미디어 서비스 모델을 제안하고자 한다.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2012.07a
• /
• pp.389-392
• /
• 2012

스마트폰의 USIM은 사용자가 별도로 인증정보를 입력할 필요가 없는 매우 편리한 인증 방법을 제공한다. 그러나 USIM에 저장된 정보가 외부로 유출될 경우 공격자가 손쉽게 정당한 사용자로 위장할 수 있는 문제점이 있다. 특히 USIM은 스마트카드에서 실행되는 어플리케이션이므로 기존에 스마트카드에 적용되었던 부채널 분석 공격 기법들이 USIM에도 적용 가능할 것으로 예상된다. 이에 본 논문에서는 스마트폰 USIM에 대한 부채널 분석 공격 가능성에 대해서 분석하고 스마트폰 USIM에 적용될 수 있는 부채널 분석 환경을 제안한다.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.13 no.1
• /
• pp.35-49
• /
• 2021

This paper presents a direct numerical simulation of turbulent flows over a bump in an open channel to examine the turbulence characteristics near divergent waves emanating from the bump and to investigate the interaction of the turbulences with the divergent waves. To verify the reliability of the simulations, the mean velocity profile and root-mean-square of velocity fluctuations are compared with previous data. The anisotropic invariant maps show that the ratio of the streamwise to spanwise velocity fluctuations plays an important role in characterizing the anisotropic nature of the separated shear layer behind the bump in the vicinity of the free surface. The vortex identification discloses a large-scale streamwise vortical structure from the mean velocity field and a cluster of small coherent structures from the instantaneous velocity field, which are responsible for the anisotropic characteristics of the turbulence beneath the free surface.