http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Challenges and Research Directions in Medical Cyber–Physical Systems
Insup Lee,Sokolsky, O.,Sanjian Chen,Hatcliff, J.,Eunkyoung Jee,BaekGyu Kim,King, A.,Mullen-Fortino, Margaret,Soojin Park,Roederer, A.,Venkatasubramanian, K. K. IEEE 2012 Proceedings of the Institute of Electrical and Ele Vol.100 No.1
<P>Medical cyber-physical systems (MCPS) are life-critical, context-aware, networked systems of medical devices. These systems are increasingly used in hospitals to provide high-quality continuous care for patients. The need to design complex MCPS that are both safe and effective has presented numerous challenges, including achieving high assurance in system software, intoperability, context-aware intelligence, autonomy, security and privacy, and device certifiability. In this paper, we discuss these challenges in developing MCPS, some of our work in addressing them, and several open research issues.</P>
Insup Lee 한국표면공학회 2017 한국표면공학회지 Vol.50 No.4
The response of AISI 310 type austenitic stainless steel to the novel low temperature plasma carburizing process has been investigated in this work. This grade of stainless steel shows better corrosion resistance and high temperature oxidation resistance due to its high chromium and nickel content. In this experiment, plasma carburizing was performed on AISI 310 stainless steel in a D.C. pulsed plasma ion nitriding system at different temperatures in H₂-Ar-CH₄ gas mixtures. The working pressure was 4 Torr (533Pa approx.) and the applied voltage was 600 V during the plasma carburizing treatment. The hardness of the samples was measured by using a Vickers micro hardness tester with the load of 100 g. The phase of carburized layer formed on the surface was confirmed by X-ray diffraction. The resultant carburized layer was found to be precipitation free and resulted in significantly improved hardness and corrosion resistance
Data Storage System Requirement for Autonomous Vehicle
Insup Kim,Ganggyu Lee,Seyoung Lee,Wonsuk Choi 제어로봇시스템학회 2022 제어로봇시스템학회 국제학술대회 논문집 Vol.2022 No.11
Autonomous Vehicle Systems (AVS) requires large set of data to not only deliver its functionality but also guarantee safety and reliability of AVS. The main functions of AVS are perception, planning and control, and big data-based machine learning algorithm is often used to perceive surrounding automatically. Like eyes and ears of human to perceive our environment, sensors such as camera, lidar and radar play a critical role for AVS. Therefore, it is also essential to process its data real-time within cache memory in computing system. While developing AVS it is required to save as much data as possible to improve AVS and to prove its reliability for its homologation as defined in UN R157. After it is in production data storage system for automated driving (DSSAD) and event data recorder (EDR) are mandated to identify responsibility of accident and to recover accident respectively. In this paper, data storage requirement of AVS is investigated by reviewing regulations and standards of AVS and its capacity requirement is estimated based on sensor data size and its requirement defined in UN R157 and UN R160 to deliver safe and reliable AVS.
Duplex Surface Treatments of Plasma Nitrocarburizing and Plasma Oxidation of SKD 11 Steel
Insup Lee,Kwang Ho Jeong,Young-Rae Cho 한국표면공학회 2007 한국표면공학회지 Vol.40 No.6
Plasma nitrocarburizing and plasma oxidizing treatments were performed to improve the wear and corrosion resistance of SKD 11 steel. Plasma nitrocarburizing was conducted for 12 h at 520℃ in the nitrogen, hydrogen and methane atmosphere to produce the ε-Fe₂?₃(N,C) phase. It was found that the compound layer produced by plasma nitrocarburising was predominantly composed of ε-phase, with a small proportion of γ'-Fe₄(N,C) phase. The thickness of the compound layer was about 5 μm and the diffusion layer was about 150 ㎛ in thickness, respectively. Plasma post oxidation was performed on the nitrocarburized samples with various oxygen/hydrogen ratio at constant temperature of 500℃ for 1 hour. The very thin magnetite (Fe₃O₄) layer 1-2 ㎛ in thickness on top of the compound layer was obtained by plasma post oxidation. It was confirmed that the corrosion characteristics of the nitrocarburized compound layer could be further improved by the application of the superficial magnetite layer.
Insup Lee 한국표면공학회 2015 한국표면공학회지 Vol.48 No.6
In this experiment, post-nitriding treatment was performed at 400℃ on AISI 316 stainless steel which was plasma carburized previously at 430℃ for 15 hours. Plasma nitriding was implemented on AISI 316 stainless steel at various gas compositions (25% N₂, 50% N₂ and 75% N₂) for 4 hours. Additionally, during post nitriding Ar gas was used with H2 and N2 to observe the improvement of surface properties. After treatment, the behavior of the hybrid layer was investigated by optical microscopy, X-ray diffraction, and micro-hardness testing. Potentiodynamic polarization test was also used to evaluate the corrosion resistance of the samples. Meanwhile, it was found that the surface hardness increased with increasing the nitrogen gas content. Also small percentage of Ar gas was introduced in the post nitriding process which improved the hardness of the hardened layer but reduced the corrosion resistance compared with the carburized sample. The experiment revealed that AISI 316L stainless steel showed better hardness and excellent corrosion resistance compared with the carburized sample, when 75% N2 gas was used during the post nitriding treatment. Also addition of Ar gas during post nitriding treatment degraded the corrosion resistance of the sample compared with the carburized sample.
Lee, Insup,Park, Ikmin Elsevier 2007 Materials science & engineering. properties, micro Vol.449 No.-
<P><B>Abstract</B></P><P>Plasma radical nitriding was performed to harden the surface of SKD 61 steel for 1–10h at temperature range of 450–550°C. The microstructures and material properties of the radical nitrided layer were characterized in order to investigate the effects of various radical nitriding processing parameters. No compound layer was formed during this process except the experiment carried out at 500°C for 10h. A diffusion depth increased with increasing treatment temperature and time (up to about 150μm). The surface hardness of radical nitrided layer was two times higher than that of the untreated surface. The main phases produced in the diffusion zone were identified to be ϵ-Fe<SUB>2-3</SUB>(N,C) and γ′-Fe<SUB>4</SUB>(N,C). The residual stress of the diffusion layer also increased with increasing treatment temperature and time due to the increase of precipitates. In addition, plasma radical nitriding produces better surface roughness, compared with conventional ion nitriding.</P>
MC-ADAPT : Adaptive Task Dropping in Mixed-Criticality Scheduling
Lee, Jaewoo,Chwa, Hoon Sung,Phan, Linh T. X.,Shin, Insik,Lee, Insup Association for Computing Machinery 2017 ACM transactions on embedded computing systems Vol.16 No.s5
<P>Recent embedded systems are becoming integrated systems with components of different criticality. To tackle this, mixed-criticality systems aim to provide different levels of timing assurance to components of different criticality levels while achieving efficient resource utilization. Many approaches have been proposed to execute more lower-criticality tasks without affecting the timeliness of higher-criticality tasks. Those previous approaches however have at least one of the two limitations; i) they penalize all lower-criticality tasks at once upon a certain situation, or ii) they make the decision how to penalize lower-criticality tasks at design time. As a consequence, they under-utilize resources by imposing an excessive penalty on low-criticality tasks. Unlike those existing studies, we present a novel framework, called MC-ADAPT, that aims to minimally penalize lower-criticality tasks by fully reflecting the dynamically changing system behavior into adaptive decision making. Towards this, we propose a new scheduling algorithm and develop its runtime schedulability analysis capable of capturing the dynamic system state. Our proposed algorithm adaptively determines which task to drop based on the runtime analysis. To determine the quality of task dropping solution, we propose the speedup factor for task dropping while the conventional use of the speedup factor only evaluates MC scheduling algorithms in terms of the worst-case schedulability. We apply the speedup factor for a newly-defined task dropping problem that evaluates task dropping solution under different runtime scheduling scenarios. We derive that MC-ADAPT has a speedup factor of 1.619 for task drop. This implies that MC-ADAPT can behave the same as the optimal scheduling algorithm with optimal task dropping strategy does under any runtime scenario if the system is sped up by a factor of 1.619.</P>