Search Results for author: Jiwon Seo

Found 25 papers, 1 papers with code

IR-UWB Radar-Based Contactless Silent Speech Recognition of Vowels, Consonants, Words, and Phrases

no code implementations15 Dec 2023 Sunghwa Lee, Younghoon Shin, Myungjong Kim, Jiwon Seo

This study demonstrated IR-UWB radar-based contactless SSR using four types of speech stimuli (vowels, consonants, words, and phrases).

Dynamic Time Warping speech-recognition +1

Low-Cost GNSS Simulators with Wireless Clock Synchronization for Indoor Positioning

no code implementations1 Jun 2023 Woohyun Kim, Jiwon Seo

Since those errors are within the coverage of each deployed simulator, it is confirmed that the proposed system with wireless clock synchronization can effectively provide periodic position updates to users where live-sky GNSS signals are unavailable.

Outdoor Positioning Position

Machine-Learning-Based Classification of GPS Signal Reception Conditions Using a Dual-Polarized Antenna in Urban Areas

no code implementations6 May 2023 Sanghyun Kim, Jiwon Seo

Consequently, when the testing dataset was collected at different locations from the training dataset, a classification accuracy of 64. 47% was obtained, which was slightly higher than the accuracy of the existing method using dual single-polarized antennas.

Performance Comparison of Numerical Optimization Algorithms for RSS-TOA-Based Target Localization

no code implementations24 Apr 2023 Halim Lee, Jiwon Seo

The average code computation time of the grid search was extremely large compared with those of the other two algorithms, and gradient descent exhibited the lowest computation time.

Testing the Channels of Convolutional Neural Networks

no code implementations6 Mar 2023 Kang Choi, Donghyun Son, Younghoon Kim, Jiwon Seo

To understand and debug convolutional neural networks (CNNs) we propose techniques for testing the channels of CNNs.

Evaluation of RF Fingerprinting-Aided RSS-Based Target Localization for Emergency Response

no code implementations19 Jun 2022 Halim Lee, Taewon Kang, Suhui Jeong, Jiwon Seo

Further, a maximum likelihood problem for target localization combining RF fingerprinting is formulated.

Seamless Accurate Positioning in Deep Urban Area based on Mode Switching Between DGNSS and Multipath Mitigation Positioning

no code implementations9 Jun 2022 Yongjun Lee, Yoola Hwang, Jae Young Ahn, Jiwon Seo, Byungwoon Park

Despite the wide usage of the GNSS in populated urban areas, it is difficult to suggest a generalized method because multipath errors are user-specific errors that cannot be eliminated by the DGNSS or a real-time kinematic technique.

Urban Road Safety Prediction: A Satellite Navigation Perspective

no code implementations6 Jun 2022 Halim Lee, Jiwon Seo, Zaher M. Kassas

From a GNSS-based navigation perspective, the reliability of GNSS signals in different locales, which is heavily dependent on the road layout within the surrounding environment, is crucial to ensure safe automated driving.

Optimal Parameter Inflation to Enhance the Availability of Single-Frequency GBAS for Intelligent Air Transportation

no code implementations3 Nov 2021 Halim Lee, Sam Pullen, Jiyun Lee, Byungwoon Park, Moonseok Yoon, Jiwon Seo

Ground-based Augmentation System (GBAS) augments Global Navigation Satellite Systems (GNSS) to support the precision approach and landing of aircraft.

Position

SFOL DME Pulse Shaping Through Digital Predistortion for High-Accuracy DME

no code implementations1 Nov 2021 Sunghwa Lee, Euiho Kim, Jiwon Seo

The Stretched-FrOnt-Leg (SFOL) pulse is a high-accuracy distance measuring equipment (DME) pulse developed to support alternative positioning and navigation for aircraft during global navigation satellite system outages.

Vocal Bursts Intensity Prediction

Scheduling Optimization Techniques for Neural Network Training

no code implementations3 Oct 2021 Hyungjun Oh, Hyeongju Kim, Jiwon Seo

In data-parallel training, we reorder the gradient computations to maximize the overlapping of computation and parameter communication; in pipeline-parallel training, we prioritize critical gradient computations to reduce the pipeline stalls. We evaluate our optimizations with twelve neural networks including a light-weight computer vision model (MobileNet) and largeNLP models (BERT and GPT-3) with up to forty eight V100 GPUs. Our scheduling algorithms effectively improve the performance of single-GPU training as well as data- and pipeline-parallel training. Compared to the respective state of the art training systems, the throughput is substantially improved for single-GPU, data-parallel, and pipeline-parallel training.

Scheduling

First Demonstration of the Korean eLoran Accuracy in a Narrow Waterway Using Improved ASF Maps

no code implementations18 Sep 2021 Woohyun Kim, Pyo-Woong Son, Sul Gee Park, Sang Hyun Park, Jiwon Seo

This letter briefly summarizes the efforts of South Korea to deploy an enhanced long-range navigation (eLoran) system, which is a terrestrial low-frequency radio navigation system that can complement GNSSs.

Enhanced Accuracy Simulator for a Future Korean Nationwide eLoran System

no code implementations13 Aug 2021 Joon Hyo Rhee, Sanghyun Kim, Pyo-Woong Son, Jiwon Seo

Once its operational performance is determined to be satisfactory, South Korea plans to move to the second phase of the program, which is a nationwide eLoran system.

Single-Antenna-Based GPS Antijamming Method Exploiting Polarization Diversity

no code implementations13 Oct 2020 Kwansik Park, Jiwon Seo

To reduce the computational complexity of the constraint matrix approach, the eigenvector constraint design scheme is adopted.

Integrity-Based Path Planning Strategy for Urban Autonomous Vehicular Navigation Using GPS and Cellular Signals

no code implementations8 Oct 2020 Halim Lee, Jiwon Seo, Zaher M. Kassas

An integrity-based path planning strategy for autonomous ground vehicle (AGV) navigation in urban environments is developed.

Navigate

Development of Record and Management Software for GPS/Loran Measurements

no code implementations24 Sep 2020 Woohyun Kim, Pyo-Woong Son, Joon Hyo Rhee, Jiwon Seo

The purpose of the developed software is to collect measurements from multiple Loran transmitter chains for performance analysis of navigation methods using Loran, and to organize the data based on time to make it easy to use them.

Signal Processing

Neural Network-Based Ranging with LTE Channel Impulse Response for Localization in Indoor Environments

no code implementations24 Sep 2020 Halim Lee, Ali A. Abdallah, Jongmin Park, Jiwon Seo, Zaher M. Kassas

The results show a receiver navigating for 100 m in an indoor environment, while receiving signals from one LTE eNodeB.

Indoor Localization

A Preliminary Study of Machine-Learning-Based Ranging with LTE Channel Impulse Response in Multipath Environment

no code implementations24 Sep 2020 Halim Lee, Jiwon Seo

Alternative navigation technology to global navigation satellite systems (GNSSs) is required for unmanned ground vehicles (UGVs) in multipath environments (such as urban areas).

BIG-bench Machine Learning

RSS-based LTE Base Station Localization Using Single Receiver in Environment with Unknown Path-Loss Exponent

no code implementations24 Sep 2020 Suhui Jeong, Halim Lee, Taewon Kang, Jiwon Seo

In this paper, we suggest a method of RSS-based LTE base station (BS) localization with a single mobile receiver when the PLE is unknown.

Effect of Outlier Removal from Temporal ASF Corrections on Multichain Loran Positioning Accuracy

no code implementations24 Sep 2020 Jongmin Park, Pyo-Woong Son, Woohyun Kim, Joon Hyo Rhee, Jiwon Seo

The widely used global navigation satellite systems (GNSSs) are vulnerable to radio frequency interference (RFI).

Practical Simplified Indoor Multiwall Path-Loss Model

no code implementations24 Sep 2020 Taewon Kang, Jiwon Seo

This paper proposed a multiwall path-loss propagation model for an indoor environment, operating at a transmission frequency of 2. 45 GHz in the industrial, scientific, and medical (ISM) radio band.

Effects of Initial Attitude Estimation Errors on Loosely Coupled Smartphone GPS/IMU Integration System

no code implementations24 Sep 2020 Kwansik Park, Woohyun Kim, Jiwon Seo

Global Positioning System (GPS) and inertial measurement unit (IMU) sensors are commonly integrated using the extended Kalman filter (EKF), for achieving better navigation performance.

Motion Planning by Reinforcement Learning for an Unmanned Aerial Vehicle in Virtual Open Space with Static Obstacles

no code implementations24 Sep 2020 Sanghyun Kim, Jongmin Park, Jae-Kwan Yun, Jiwon Seo

In this study, we applied reinforcement learning based on the proximal policy optimization algorithm to perform motion planning for an unmanned aerial vehicle (UAV) in an open space with static obstacles.

Motion Planning reinforcement-learning +1

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