2,702 research outputs found
An Architecture of Car Diagnostic Service by using Enhanced Security Protocol
No full textIn the automotive industry, Ethernet is being used as a vehicle communication network in order to increase the speed and data bandwidth of the vehicle network. Due to the characteristic of the disclosed protocol, Ethernet can be easily applied to various industrial fields. Also,since it is a standard specification based on open protocol, there aresome advantages, such as the compatibility between existing functions and other industrial fields. In recent years, automotive operating systems such as AUTOSAR have also supported Ethernet as a vehicle communication network. This is because functions such as advanced driver assistance system (ADAS) and around view monitoring system (AVMS) in vehicles require large data transfer and speed. It is also used to diagnose the vehicle remotely using Ethernet and to provide diagnostic information to a driver. However, the characteristic of the disclosed protocol causes Ethernet to be vulnerable to the security issues. Therefore, to ensure the safety of the vehicle and the driver, the enhanced method for the security and controlling access to the Ethernet is imperative. In this paper, we propose a security and authentication protocol based on IPSec that encrypts the diagnostic information of the vehicle. With this security protocol, we can encrypt and authenticate diagnosis information of the vehicle on Ethernet. Therefore, the safety level of the vehicle can be enhanced.And,it will prevent to access diagnosis information from unauthorized user.1
OSEK/VDX-Based Application Software Development Using Generic Embedded System
No full textOSEK/VDX (Open Systems and their Interfaces
for the Electronics in Motor Vehicles/Vehicle Distributed
eXecutive) is an open platform that has produced specifications
for an operating system, a communication and a network
management for automotive embedded systems to enhance
software portability and reusability. Generic Embedded System
developed by DGIST provides an environment to develop an
automotive embedded software easily. In this paper, we introduce
the Generic Embedded System and OSEK Development
Tools and present a detailed case study to describe an example
of OSEK-based automotive software application of RCS
(Roomlamp Control System). Automotive engineers can learn
easily OSEK OS application software and utilize this case study
to other application software development through this case
study.1
Erratum: 3D bioprinted in vitro secondary hyperoxaluria model by mimicking intestinal-oxalatemalabsorption-related kidney stone disease (Applied Physics Reviews (2022) 9 (041408) DOI: 10.1063/5.0087345)
No full text© 2023 Author(s).This article was originally published online on 21 November 2022 with an incorrect affiliation identifier for author Dong-Woo Cho. It is correct as it appears above. All online versions of this article were corrected on 23 November 2022. AIP Publishing apologizes for this error.11Nsciescopu
Unimodality of Betti numbers for Hamiltonian circle actions with index-increasing moment Maps
No full textThe unimodality conjecture posed by Tolman in [L. Jeffrey, T. Holm, Y. Karshon, E. Lerman and E. Meinrenken, Moment maps in various geometries, http://www.birs.ca/workshops/2005/05w5072/report05w5072.pdf] states that if (M,ω) is a 2n-dimensional smooth compact symplectic manifold equipped with a Hamiltonian circle action with only isolated fixed points, then the sequence of Betti numbers {b0(M),b2(M),...,b2n(M)} is unimodal, i.e. bi(M) ≤ bi+2(M) for every i < n. Recently, the author and Kim [Y. Cho and M. Kim, Unimodality of the Betti numbers for Hamiltonian circle action with isolated fixed points, Math. Res. Lett. 21(4) (2014) 691-696] proved that the unimodality holds in eight-dimensional case by using equivariant cohomology theory. In this paper, we generalize the idea in [Y. Cho and M. Kim, Unimodality of the Betti numbers for Hamiltonian circle action with isolated fixed points, Math. Res. Lett. 21(4) (2014) 691-696] to an arbitrary dimensional case. We prove the conjecture in arbitrary dimension under the assumption that the moment map H : M → R is index-increasing, which means that ind(p) < ind(q) implies H(p) < H(q) for every pair of critical points p and q of H, where ind(p) is the Morse index of p with respect to H. © World Scientific Publishing Company1111sciescopu
Crucial role of Ni-doping to interfacial Li2MnO3 layer of High-performance Ni-rich layered cathode in Lithium-Ion batteries
No full text© 2022 Elsevier B.V.The surface instability of Ni3+ in Ni-rich layered oxide cathode materials is recognized as an obstacle in high-energy–density lithium-ion batteries. Researchers have previously attempted to solve this issue using a protective layer with a stable substance. Despite the popularity Ni-rich layered oxides, their exceptionally unstable surface has not been investigated comprehensively. Ni-rich layered oxides include lithium impurities and have a fragile surface, forming a NiO bi-phase. In this study, we perform Li2MnO3 coating to enable Ni doping via simple stirring and heat treatment combined, while considering the surface states of Ni-rich layered oxide, where lithium impurities are inevitable and a NiO bi-phase may exist. It is discovered that the tailoring interface consuming surface NiO is critical for mitigating the surface resistance. Among the samples with Li2MnO3 coating, only the sample prepared via 800 °C heating indicates the presence of Ni-doped Li2MnO3 based on electrochemical de-lithiation at 4.65 V vs. Li/Li+. It is effective in reducing NiO and stabilizing the surface for a high cycle life of 88.3% at the 100th cycle and a high rate capability of 76.9% at 5C, whereas a Li2MnO3-coated sample exhibits a cycle life of 70.4% at the 100th cycle and a rate capability of 29.1% at 5C. The surface is investigated via X-ray photoelectron spectroscopy, scanning transmission electron microscopy, and time-of-flight secondary ion mass spectroscopy analyses.N
Characteristics of two-dimensional MoS2 grown on GaN substrates by metal-organic chemical vapor deposition
No full textSystems biology for reverse aging
No full textCellular senescence is an irreversible and permanent cell cycle arrest in response to internal and external stresses. Its unresponsiveness to growth factor signals distinguishes it from a potentially reversible state, quiescence. Cellular senescence can inhibit tumor development by blocking proliferation of damaged cells, but as senescent cells become accumulated in a tissue, they can contribute to the promotion of agerelated diseases such as cancer by secreting inflammatory cytokines [1]. © 2021 Cho et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
The antihypertensive effects of the Jamaican Cho-Cho (Sechium edule)
No full textThe experiments reported in this study constitute a preliminary investigation into the possible hypotensive effect of the Jamaican Cho-Cho (Sechium edule). Experiments were conducted in a random and blind fashion on two sub species of Sechium edule. Both the pulp and the peel were examined for hypotensive activity. Water-soluble extracts were prepared from these components of the fruit and injected into anaesthetised rats. Various cardiovascular parameters were measured including heart rate, mean arterial pressure (MAP) and several ECG intervals. We report that all extracts tested produced a fall in blood pressure with little change in ECG intervals. Extract B produced the least change in heart rate with a fall in MAP of approximately 23 mmHg. Changes in heart rate with all extracts appeared to be minimal as an ED25 value could only be determined for extract A, and ED10 values could not be evaluated for extracts C and D. The mechanism(s) by which these extracts produce their hypotensive effects could not be determined in these preliminary experiments. However, it appears not to involve direct effects on cardiac tissue. This conclusion is based on the finding that it took a minimum of 10 to 15 seconds for the hypotensive action to manifest post bolus. Future experiments will be aimed at delineating the mechanism(s) involved in decreasing MAP.Peer reviewedfinal article publishe
Nota su Eschilo, Cho. 65
No full textThe author defends the reading ἄκραντος in the sense of “unfinished” in Aesch. Cho. 65
충격파-강한 와류 상호작용 문제를 통한 고차 정확도 수치기법의 성능에 관한 연구
No full text학위논문 (석사)-- 서울대학교 대학원 : 공과대학 기계항공공학부, 2018. 2. 김종암.본 연구에서는 고차 정확도 수치기법이 충격파를 동반한 압축성 유동 문제에서 어떠한 성능을 갖는지 분석하였다. 이를 위해 충격파-강한 와류 상호작용 문제를 불연속 갤러킨 (DG) 기법으로 해석하고, 수치기법들 간의 성능을 정성적 및 정량적인 방법들로 분석하였다.
본 문제에서 충격파-와류 상호작용 현상을 이차원 비섬정 유동으로 모델링하였다. 충격파와 와류의 상호작용으로 인해 복잡한 충격파 구조, 와류 구조, 음파의 발달과 같은 물리현상들이 발생한다. 비정상 수치해석 결과를 바탕으로 유동의 물리현상을 관찰 및 분석하고, 고차 정확도 수치기법들의 결과를 비교할 기준을 세울 수 있었다. DG기법에 다차원 공간 제한자 기법 (MLP) 기반의 고차 정확도 충격파 포착기법을 적용하여 다양한 종류와 크기의 격자들에 대해 본 문제를 해석하였다. 그리고, 복잡한 유동 구조를 묘사할 수 있는 지와 유동의 비정상 수치해를 평가함으로써 수치기법들을 비교 및 분석하였다.
충격파-강한 와류 상호작용 문제에서 나타난 고차 정확도 수치기법의 정확도 차수 (order-of-accuracy) 감소의 원인을 규명하기 위해 추가적 문제들을 설정하였다. 이 문제들을 통해 각 요인이 정확도 차수 저하에 어떠한 영향을 미치는지 파악할 수 있었다. 그 결과, 사영 오차와 충격파에 의해 발생한 진동이 고차 정확도 수치기법에서 정확도 차수 저하의 주요 원인으로 밝혀졌다.The present works deal with the performance of higher-order CFD methods in compressible flows with shock waves. We solve the shock wave-strong vortex interaction problem with the discontinuous Galerkin (DG) method, and the performance of the numerical schemes is analyzed in qualitative and quantitative manners.
We model the shock wave-vortex interaction phenomenon as a two-dimensional inviscid flow problem. Due to the interaction of the shock wave and vortex, physical phenomena such as complex shock structure, vortex structure, and evolution of acoustic waves occur. We observe and analyze these flow physics with the unsteady numerical results, and establish the criteria to compare the results of the higher-order methods. As shock capturing methods, hierarchical multi-dimensional limiting process (hMLP) and hMLP with the troubled-boundary detector (hMLP_BD) are used with the DG method. The DG method with hMLP and hMLP_BD are applied to solve the problem in meshes of various types and sizes. Then, the numerical schemes are compared and analyzed by verifying capability to describe complex flow physics and evaluating unsteady flow solutions.
In order to identify the causes of the order-of-accuracy degradation of higher-order methods in the shock wave-strong vortex problem, additional problems are set up and tested. Through these additional tests, we can examine the effect of each factor on order-of-accuracy degradation. As a result, projection error and shock-driven oscillations are the main causes of order-of-accuracy degradation in higher-order methods.Chapter 1 Introduction 1
1.1 Higher-order CFD Methods 1
1.2 Objectives of Thesis 2
Chapter 2 Numerical Methods 4
2.1 Governing Equations 4
2.2 Higher-order Discretization Methods 4
2.2.1 Discontinuous Galerkin Method 4
2.2.2 Explicit Time Integration 5
2.3 Higher-order Limiting Strategy 6
2.3.1 Basic Concept of Multi-dimensional Limiting Process 6
2.3.2 Multi-dimensional Limiting Process for Higher-order Methods 7
2.3.3 Cure for Subcell Gibbs Oscillations of hMLP 9
Chapter 3 Problem Description 11
3.1 Shock Wave-Strong Vortex Interaction Problem 11
3.1.1 Numerical Test Cases 13
3.1.2 Reference Lines 15
3.2 Flow Physics of the Problem 16
3.2.1 Shock Structure 16
3.2.2 Vortex Structure 21
3.2.3 Acoustic Waves 23
3.3 Reference Solution 25
3.3.1 Setting the Reference Solution 25
3.3.2 Non-physical Oscillation 26
Chapter 4 Numerical Results 28
4.1 Two-dimensional Contour 28
4.2 Solution Distribution along the Reference Lines 30
4.3 Order Tests at the Reference Lines 34
4.4 Discussion on the Numerical Results 38
Chapter 5 Analysis of Order-of-Accuracy Degradation 40
5.1 Factors Affecting Order-of-Accuracy Degradation 40
5.2 Additional Tests 40
5.2.1 Vortex Transport 41
5.2.2 Vortex behind Stationary Shock 43
5.2.3 Vortex behind Stationary Shock inside Cells 45
5.2.4 Vortex behind Non-aligned Stationary Shock 46
5.3 Effect of Each Factor on Order-of-Accuracy Degradation 48
Chapter 6 Conclusions 51
Bibliography 53Maste
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