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Multi-Agent Deep Reinforcement Learning-Based Resource Allocation in HPC/AI Converged Cluster

Computers, Materials & Continua 2022年第9期72卷 4375-4395页

作者： Jargalsaikhan Narantuya jun-sik shin Sun Park JongWon Kim Department of Cloud Kakao Enterprise CorpSeongnam13494Korea AI Graduate School Gwangju Institute of Science and Technology(GIST)Gwangju61005Korea

As the complexity of deep learning(DL)networks and training data grows enormously,methods that scale with computation are becoming the future of artificial intelligence(AI)*** this regard,the interplay between machine learning(ML)and high-performance computing(HPC)is an innovative paradigm to speed up the efficiency of AI research and ***,building and operating an HPC/AI converged system require broad knowledge to leverage the latest computing,networking,and storage ***,an HPC-based AI computing environment needs an appropriate resource allocation and monitoring strategy to efficiently utilize the system *** this regard,we introduce a technique for building and operating a high-performance AI-computing environment with the latest ***,an HPC/AI converged system is configured inside Gwangju Institute of Science and Technology(GIST),called GIST AI-X computing cluster,which is built by leveraging the latest Nvidia DGX servers,high-performance storage and networking devices,and various open source ***,it can be a good reference for building a small or middlesized HPC/AI converged system for research and educational *** addition,we propose a resource allocation method for DL jobs to efficiently utilize the computing resources with multi-agent deep reinforcement learning(mDRL).Through extensive simulations and experiments,we validate that the proposed mDRL algorithm can help the HPC/AI converged cluster to achieve both system utilization and power consumption *** deploying the proposed resource allocation method to the system,total job completion time is reduced by around 20%and inefficient power consumption is reduced by around 40%.

关键词： Deep learning HPC/AI converged cluster reinforcement learning

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Efects on nano zero-valent iron reactivity of interactions between hardness, alkalinity, and natural organic matter in reverse osmosis concentrate

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Journal of Environmental Sciences 2013年第11期25卷 2177-2184页

作者： Yuhoon Hwang Hang-sik shin Department of Environmental Engineering Technical University of Denmark Department of Civil and Environmental Engineering Korea Advanced Institute of Science and Technology

Nanoscale zero-valent iron （NZVI） is considered to have potential to reduce nitrate in the concentrate generated by high pressure membrane processes aimed at water reuse. However, it is necessary to verify the effect of the matrix components in the concentrates on NZVI reactivity. In this study, the influence of hardness, alkalinity, and organic matter on NZVI reactivity was evaluated by the response surface method （RSM）. Hardness （Ca/＋） had a positive effect on NZVI reactivity by accelerating iron corrosion. In contrast, alkalinity （bicarbonate; HCO3） and organic matter （humic acid; HA） had negative effects on NZVI reactivity due to morphological change to carbonate green rust, and to competitive adsorption of HA, respectively. The validity of the statistical prediction model derived from RSM was confirmed by an additional confirmation experiment, and the experimental result was within the 95% confidential interval. Therefore, it can be indicated that the RSM model produced results that were statistically significant.

关键词： nitrate reduction concentrate treatment response surface method nano zero valent iron

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Experimental assessment of two-phase bubble pump for solar water heating

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Journal of Central South University 2012年第6期19卷 1590-1599页

作者： CHUNG Han-shik WOO Ju-sik shin Yong-han KIM jun-hyo JEONG Hyo-min Institute of Marine Industry Department of Mechanical and Precision EngineeringGyeongsang National University445 Inpyeong DongTongyeongGyeongsangnamdo650-160Korea Department of Mechanical and Precision Engineering Gyeongsang National University445 Inpyeong DongTongyeongGyeongsangnamdo650-160Korea Division of Marine Engineering Mokpo National Maritime UniversityHaeyangdaehang-Ro 91Mokpo-siJeollanam-do530-729Korea

The research goal is to develop a new solar water heater system(SWHS) that uses a solar bubble pump instead of an electric *** pump is powered by the steam produced from an evacuated tube ***,heat could be transferred downward from the collector to a hot water storage *** designed system consists of two sets of heat-pipe evacuated tube collectors,a solar bubble pump installed at an upper level and a water storage tank with a heat exchanger at a lower *** heads of 1 and 5 m were *** bubble pump could operate at the collector temperature of about 90-100 ℃ and vapor gage pressure of 80-90 *** is found that water circulation within the SWHS depends on the incident solar intensity and system discharge *** investigations are conducted to obtain the system thermal efficiencies from the hourly,daily and long-term performance *** thermal performance of the proposed system is compared with conventional solar water *** results show that the proposed system achieves system characteristic efficiency of 10% higher than that of the conventional systems using electric pump if taking the consumption of electric power into *** the former is a zero carbon system.

关键词： two-phase bubble pump solar water heater system (SWHS) zero carbon

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Effect of Ni and Mn on the Mechanical Properties of 22Cr Microduplex Stainless Steel

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Acta Metallurgica Sinica(English Letters) 2015年第1期28卷 32-38页

作者： jun-Young Park Yong-sik Ahn Department of Materials Science and Engineering Pukyong National University

The tensile properties of 22Cr–2Ni–4Mn–0.2N micro-duplex stainless steels with different Ni and Mn contents were investigated. Duplex stainless steels were vacuum induction melted and hot rolled, then annealed at 1,000–1,100 °C, at which temperature both the austenite and ferrite phases were stable. The volume fraction of the ferrite phase was markedly affected by the alloying elements of Mn and Ni; 1 wt% of Mn was equivalent to 0.4 wt% of Ni. All of the steels tested at room temperature showed the common strain-hardening behavior, while the steels tested at lower temperatures（-30 or-50 °C）showed a distinct inflection point in their stress–strain curves, which resulted from the transformation of the austenite to straininduced martensite. The onset strain（e0） of the inflection point in the stress–strain curve depended on the Md30 value of the steel. Testing at lower temperatures resulted in smaller e0 and consequently higher strengths and fracture strains（ef）. The tensile behavior was examined from the perspective of austenite stability of the micro-duplex stainless steels with the different Ni and Mn contents.

关键词： Duplex stainless steel Microstructure Mechanical property Alloy composition

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Modeling asymmetric fracture mechanics of Mg alloy wire in drawing process

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Journal of Magnesium and Alloys 2024年第5期12卷 2057-2069页

作者： Sunghoon Choi Jongwon shin Joung sik Suh Dongchoul Kim Department of Mechanical Engineering Sogang UniversitySeoul04107Republic of Korea Advanced Metals Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea

In this study,a numerical analysis was conducted on the ductile fracture of a 2-mm diameter Mg-1Zn-0.5Mn-0.5Sr-0.1Ca alloy wire during *** hexagonally close-packed crystal structure of Mg alloys causes asymmetric fracture behavior,especially in the compression *** aim of this study is to develop a comprehensive damage model for Mg alloy wire that accurately predicts ductile fracture,with a focus on the compression region.A novel experimental method was introduced to measure the ductile fracture of Mg alloy wires under different stress *** wire drawing process was simulated using the Generalized Incremental Stress-State dependent damage(GISSMO)Model and the Semi-Analytical Model for Polymers(SAMP)*** damage model's prediction and the experimental results were found to be in excellent agreement,especially in determining crack *** analysis established a safe zone diagram for die angle and reduction ratio,and experimental validation confirmed the feasibility of this *** proposed damage model can provide a practical and reliable analysis for optimizing the drawing process of Mg alloy wire.

关键词： Mg alloy Wire drawing Finite element method Damage model Safe zone diagram

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Single-atom Pd catalyst anchored on Zr-based metal-organic polyhedra for Suzuki-Miyaura cross coupling reactions in aqueous media

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Nano Research 2021年第2期14卷 486-492页

作者： Seongsoo Kim Seohyeon Jee Kyung Min Choi Dong-sik shin Division of Chemical and Bioengineering Kangwon National UniversityGangwon-do 24341Republic of Korea Department of Chemical and Biological Engineering Sookmyung Womens University100 Cheongpa-ro 47-gilYongsan-guSeoul 04310Republic of Korea

The challenge for single-atom catalysts in various C-C cross coupling reaction exists in the development of solid supporting *** has been desired tofind a supporting material designed in molecular level to anchor a single-atom catalyst and provide high degree of dispersion and substrate access in aqueous ***,we prepared discrete cages of metal-organic polyhedra anchoring single Pd atom(MOP-BPY(Pd))and successfully performed a Suzuki-Miyaura cross coupling reaction with various substrates in aqueous *** was revealed that each tetrahedral cage of MOP-BPY(Pd)has 4.5 Pd atoms on average and retained its high degree of dispersion up to 3 months in *** coupling efficiencies of the Suzuki-Miyaura cross coupling reaction exhibited more than 90.0%for various substrates we have tested in the aqueous media,which is superior to those of the molecular Pd complex and metal-organic framework(MOF)anchoring Pd ***,MOP-BPY(Pd)was successfully recovered and recycled without performance degradation.

关键词： metal-organic polyhedra Suzuki-Miyaura cross coupling reaction structure characterization aqueous phase reaction high-degree of dispersion

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A hybrid storage technology for low power consumption and high I/O performance in an IPTV set-top box

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Journal of Central South University 2012年第5期19卷 1267-1275页

作者： KIM Deok-hwan YANG jun-sik Department of Electronics Engineering Inha UniversityIncheon 402-751Korea

A new method of prefetching data blocks from the NVCache to the page cache in main memory and cascading prefetching n-blocks from a hard disk to the NVCache together was proposed to reduce the spin-up frequency of a hybrid hard disk drive and thus enhance I/O *** proposed method consists of three steps:1) Analyzing the pattern of read requests in block units;2) Determining the number of blocks prefetched to the NVCache;3) Replacing blocks in the NVCache according to the block replacement *** proposed method can reduce the latency time of a hybrid hard disk and optimize the power consumption of an IPTV set-top *** results show that the proposed method provides better average response time compared to an existing adaptive multistream prefetching(AMP) method by 25.17%.It also reduces by 20.83% the average power consumption over that of the existing external caching in energy saving storage system(EXCES) method.

关键词： IPTV set-top box hybrid hard disk prefetching spin-down low power consumption

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Evaluation of vitamin D level in patients from neurosurgical intensive care unit

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Neural Regeneration Research 2013年第16期8卷 1528-1534页

作者： Ho jun Yi Je Hoon Jeong Eun-Sun Jin Il Young shin Hyung sik Hwang Seung-Myung Moon Department of Neurosurgery Hangang Sacred Heart Hospital College of Medicine Hallym University Department of Neurosurgery Soon Chun Hyang University Bucheon Hospital Gyeonggi-do Department of Cardiology Kyung Hee University Hospital at Kangdong Kyung Hee University

Vitamin D plays an important role in maintaining normal bone metabolism. Recent studies have suggested that vitamin D influences many other physiological processes, including muscle function, cardiovascular homeostasis, nerve function, and immune response. Furthermore, accumulated evidence suggests that vitamin D also mediates the immune system response to infection. Critical neurosurgical patients have higher infection and mortality rates. To correlate vitamin D deficiency to the immunological status of neurosurgical intensive care unit patients, we detected serum vitamin D level in 15 patients with clinically suspected infection and 10 patients with confirmed infection. Serum level of 25-hydroxyvitamin D, the primary circulating form of vitamin D, was significantly decreased in patients with suspected or confirmed infection after a 2-week neurosurgical intensive care unit hospitalization, while serum level of 1,25-dihydroxyvitamin D, the active form of vitamin D, was significantly decreased in patients after a 4-week neurosurgical intensive care unit hospitalization. These findings suggest that vitamin D deficiency is linked to the immunological status of neurosurgical intensive care unit patients and vitamin D supplementation can improve patient＇s immunological status.

关键词： neural regeneration vitamin D white blood cell immune deficiency infectious diseases intensivecare unit neurosurgery neuroregeneration

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A Computational Study of Thrust Vectoring Control Using Dual Throat Nozzle

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Journal of Thermal Science 2010年第6期19卷 486-490页

作者： Choon sik shin Heuy Dong Kim Toshiaki Setoguchi Shigeru Matsuo Department of Mechanical Engineering Andong National University Department of Mechanical Engineering Saga University

Dual throat nozzle (DTN) is fast becoming a popular technique for thrust vectoring. The DTN is designed with two throats, an upstream minimum and a downstream minimum at the nozzle exit, with a cavity in between the upstream throat and exit. In the present study, a computational work has been carried out to analyze the performance of a dual throat nozzle at various mass flow rates of secondary flow and nozzle pressure ratios (NPR). Two-dimensional, steady, compressible Navier-Stokes equations were solved using a fully implicit finite volume scheme. The present computational results were validated with available experimental data. Based on the present results, the control effectiveness of thrust-vectoring is discussed in terms of the thrust coefficient and the coefficient of discharge.

关键词： Compressible Flow Dual Throat Nozzle Thrust Vector Control Shock Wave Supersonic Flow

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Reliability of flip-chip bonded RFID die using anisotropic conductive paste hybrid material

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 175-181页

作者： jun-sik LEE jun-Ki KIM Mok-Soon KIM Namhyun KANG Jong-Hyun LEE Advanced Joining Technology Team/Microjoining Center Korea Institute of Industrial Technology(KITECH) Yeonsu-gu Incheon 406-840 Korea School of Materials Science & Engineering Inha University Department of Materials Science & Engineering Pusan National University Department of Materials Science & Engineering Seoul National University of Technology

A reliability of flip-chip bonded die as a function of anisotropic conductive paste (ACP) hybrid materials, bonding conditions, and antenna pattern materials was investigated during the assembly of radio frequency identification(RFID) inlay. The optimization condition for flip-chip bonding was determined from the behavior of bonding strength. Under the optimized condition, the shear strength for the antenna printed with paste-type Ag ink was larger than that for Cu antenna. Furthermore, an identification distance was varied from the antenna materials. Comparing with the Ag antenna pattern, the as-bonded die on Cu antenna showed a larger distance of identification. However, the long-term reliability of inlay using the Cu antenna was decreased significantly as a function of aging time at room temperature because of the bended shape of Cu antenna formed during the flip-chip bonding process.

关键词： RFID inlay ACP flip-chip, bonding process reliability

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