https://scholar.dgist.ac.kr/handle/20.500.11750/151 2026-04-04T14:57:48Z 2026-04-04T14:57:48Z Shin, Jongho Baek, Youngmi Lee, Jaeseong Lee, Seonghun https://scholar.dgist.ac.kr/handle/20.500.11750/9542 2025-07-24T07:32:10Z 2018-12-31T15:00:00Z

Title: Cyber-physical attack detection and recovery based on RNN in automotive brake systems Author(s): Shin, Jongho; Baek, Youngmi; Lee, Jaeseong; Lee, Seonghun Abstract: The violation of data integrity in automotive Cyber-Physical Systems (CPS) may lead to dangerous situations for drivers and pedestrians in terms of safety. In particular, cyber-attacks on the sensor could easily degrade data accuracy and consistency over any other attack, we investigate attack detection and identification based on a deep learning technology on wheel speed sensors of automotive CPS. For faster recovery of a physical system with detection of the cyber-attacks, estimation of a specific value is conducted to substitute false data. To the best of our knowledge, there has not been a case of joining sensor attack detection and vehicle speed estimation in existing literatures. In this work, we design a novel method to combine attack detection and identification, vehicle speed estimation of wheel speed sensors to improve the safety of CPS even under the attacks. First, we define states of the sensors based on the cases of attacks that can occur in the sensors. Second, Recurrent Neural Network (RNN) is applied to detect and identify wheel speed sensor attacks. Third, in order to estimate the vehicle speeds accurately, we employWeighted Average (WA), as one of the fusion algorithms, in order to assign a different weight to each sensor. Since environment uncertainty while driving has an impact on different characteristics of vehicles and cause performance degradation, the recovery mechanism needs the ability adaptive to changing environments. Therefore, we estimate the vehicle speeds after assigning a different weight to each sensor depending on driving situations classified by analyzing driving data. Experiments including training, validation, and test are carried out with actual measurements obtained while driving on the real road. In case of the fault detection and identification, classification accuracy is evaluated. Mean Squared Error (MSE) is calculated to verify that the speed is estimated accurately. The classification accuracy about test additive attack data is 99.4978%. MSE of our proposed speed estimation algorithm is 1.7786. It is about 0.2 lower than MSEs of other algorithms. We demonstrate that our system maintains data integrity well and is safe relatively in comparison with systems which apply other algorithms. © 2018 by the authors.

2018-12-31T15:00:00Z Kahng, Sungtek Jeon, Jinsu Park, Taejoon https://scholar.dgist.ac.kr/handle/20.500.11750/2613 2025-07-24T07:25:44Z 2014-12-31T15:00:00Z

Title: An Orthogonally Polarized Negative Resonance CRLH Patch Antenna Author(s): Kahng, Sungtek; Jeon, Jinsu; Park, Taejoon Abstract: A novel fully-printed microstrip antenna with negative first resonance and dual polarization is proposed. The radiator is printed on the 1-layer substrate instead of multilayers. The -1st resonance results from a composite right- and left-handed(CRLH) structure that has a circumferentially interlocked gap capacitively coupling a patch with a shorted-ring. This compact antenna is provided with a dual-polarization capability by creating two orthogonal linear polarizations in one body with coaxial feeds. The design is carried out by doing full-wave EM field simulation which is compared with the measurement of the fabricated antenna prototype. The measured results give the gain of 5 dBi and the efficiency of 78% at the -1st resonance mode as the center frequency of a downlink channel of the bandwidth over 20 MHz with 29 dB polarization isolation for mobile communication. © The Korean Institute of Electrical Engineers.

2014-12-31T15:00:00Z Kwon, W.H.[Kwon, Wook Hyun] Han, S.[Han, Soo Hee ] https://scholar.dgist.ac.kr/handle/20.500.11750/3139 2025-07-24T07:28:04Z 2013-12-31T15:00:00Z

Title: Recent Trends in Receding Horizon Control Author(s): Kwon, W.H.[Kwon, Wook Hyun]; Han, S.[Han, Soo Hee ] Abstract: This article introduces recent trends in RHC (Receding Horizon Control), also known as MPC (Model Predictive Control), that has been well recognized in industry and academy as a systematic approach for optimal design and constraint management. Constrained and robust RHCs will be briefly reviewed with milestone results. Among the diverse developments and achievements of RHCs, implementation issues will be focused on, together with the latest applications. In particular, this article introduces results on how to solve a finite horizon open-loop optimal control problem in an efficient way, together with code generation for real-time execution and easy implementation. Instead of traditional applications such as refineries and petrochemical plants, this article highlights some selected emerging applications, such as energy management systems and mechatronics, that have resulted from state-of-the-art high performance computing power and advanced numerical schemes.

2013-12-31T15:00:00Z Park, Ji-Sang Kang, Joongoo Yang, Ji-Hui Metzger, Wyatt Wei, Su-Huai https://scholar.dgist.ac.kr/handle/20.500.11750/2352 2025-07-24T07:25:56Z 2015-01-14T15:00:00Z

Title: Stability and electronic structure of the low-Sigma grain boundaries in CdTe: a density functional study Author(s): Park, Ji-Sang; Kang, Joongoo; Yang, Ji-Hui; Metzger, Wyatt; Wei, Su-Huai Abstract: Using first-principles density functional calculations, we investigate the relative stability and electronic structure of the grain boundaries (GBs) in zinc-blende CdTe. Among the low-Σ-value symmetric tilt Σ3 (111), Σ3 (112), Σ5 (120), and Σ5 (130) GBs, we show that the Σ3 (111) GB is always the most stable due to the absence of dangling bonds and wrong bonds. The Σ5 (120) GBs, however, are shown to be more stable than the Σ3 (112) GBs, even though the former has a higher Σ value, and the latter is often used as a model system to study GB effects in zinc-blende semiconductors. Moreover, we find that although containing wrong bonds, the Σ5 (120) GBs are electrically benign due to the short wrong bond lengths, and thus are not as harmful as the Σ3 (112) GBs also having wrong bonds but with longer bond lengths. © 2015 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

2015-01-14T15:00:00Z