Resource-based mobility management for video users in 5G using catalytic computing

Sharma, Vishal,You, Ilsun,Kumar, Ravinder Elsevier 2018 Journal of Computer Communications Vol.118 No.-

<P><B>Abstract</B></P> <P>The upcoming 5G era emphasizes on a dramatic increase in the transmission rate of smartphone traffic. With more users operating at high rates, the type of data shared over the network is going to be complex and a majority of it will include video traffic. Such complex structure of traffic and heavy load over the components of the network are difficult to control. Further, the mobility of users adds up to this issue and makes it difficult to manage and operate the network without any breakdown. Thus, it important to control traffic as well as manage the mobility of users to provide efficient communication, which can support video traffic at high delivery rates. This paper proposes a novel resource-based mobility management approach for 5G networks comprising video users. A novel resource sharing paradigm, termed as “Catalytic Computing”, provides efficient management of user mobility as well as network resources. The proposed approach relies on Homogeneous discrete Markov model for user mobility patterns and a novel n-step algorithm for congestion prediction and selection of optimal routes between the serving terminals. An activation energy based handover mechanism is also presented in this paper, which reduces the handover latency in comparison with the existing solutions. The evaluation presented in the paper suggests that the proposed approach provides a minimum of 5.9 ms, maximum of 9.1 ms and an average of 6.5 ms latency during handoffs.</P>

배기가스 정화장치의 입ㆍ출구 형상에 따른 배압 및 유동특성에 관한 연구

안진렬(Jin Yeol Ahn),구자형(Ja Hyoung Ku),박종근(Jong Keun Park),김종원(Jong Won Kim) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

The pressure drop and the uniformity of incoming exhaust gas are becoming more and more important design factors to develop catalytic converter. The catalytic converter optimizing these factors might minimize engine power resistance and maximize the performance and durability of catalytic converter. In this regard, this paper is dealt with the catalytic converter's performance depending upon the geometry of inlet and outlet parts, and inferred the best combination of inlet and outlet geometry to optimize converter performance. Good advantage is taken of numerical analysis for estimating reciprocal influences of each factor. That analysis shows that the pressure drop and flow uniformity is subject to the inlet and outlet geometry of catalytic converter, and the effective inlet and outlet geometry of converter is a concave shape and a S-shape part respectively in the view point of the pressure drop and flow uniformity.

공정시스템,이동현상,화학공정안전 : 전산유체역학 기법을 이용한 촉매 멤브레인 반응기 해석

박정수 ( Park Jeong Su ),서정철 ( Seo Jeong Cheol ),신동일 ( Sin Dong Il ),윤인섭 ( Yun In Seob ) 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.6

Results of the analysis of a catalytic membrane reactor for the water gas shift (WGS) reaction are presented and discussed using CFD (computational fluid dynamics) technique. Reaction kinetic expressions were researched, and Langmuir-Hinshelwood kinetic`s expression gives the best result. The optimal operation temperature was found out to be 630K. A CFD module for the palladium (Pd) membrane, separating hydrogen, was also developed, simulated and compared to the references. It easily simulates the effects of the reaction temperature, pressure, sweep gas flow rate, sweep gas flow direction and palladium membrane thickness on the CO conversion of the catalytic membrane reactor. Results of the analysis are very useful in the commercialization of the hydrogen-generation process, and the developed simulation framework is easily adaptable for further design and modification when more detailed profiles are necessary.

Numerical Analysis of Flow Uniformity in Selective Catalytic Reduction (SCR) Process Using Computational Fluid Dynamics (CFD)

손병현 국제문화기술진흥원 2022 International Journal of Advanced Culture Technolo Vol.10 No.3

The NOx removal performance of the SCR process depends on various factors such as catalytic factors (catalyst composition, shape, space velocity, etc.), and temperature and flow rate distribution of the exhaust gas. Among them, the uniformity of the flow flowing into the catalyst bed plays the most important role. In this study, the flow characteristics in the SCR reactor in the design stage were simulated using a three-dimensional numerical analysis technique to confirm the uniformity of the airflow. Due to the limitation of the installation space, the shape of the inlet duct was compared with the two types of inlet duct shape because there were many curved sections of the inlet duct and the duct size margin was not large. The effect of inlet duct shape, guide vane or mixer installation, and venturi shape change on SCR reactor internal flow, airflow uniformity, and space utilization rate of ammonia concentration were studied. It was found that the uniformity of the airflow reaching the catalyst layer was greatly improved when an inlet duct with a shape that could suppress drift was applied and guide vanes were installed in the curved part of the inlet duct to properly distribute the process gas. In addition, the space utilization rate was greatly improved when the duct at the rear of the nozzle was applied as a venturi type rather than a mixer for uniform distribution of ammonia gas.

SCR 시스템 내 암모니아 분사 균일도 개선을 위한 AIG 설계에 관한 해석적 연구

서문혁(Moon-Hyeok Seo),장혁상(Hyuksang Chang) 한국청정기술학회 2012 청정기술 Vol.18 No.4

Optimizing reactor performance and kinetics of formic acid production via computational fluid dynamics during heterogeneous catalytic hydrogenation of CO₂ using Ru-Based catalyst

( Tesfalem Aregawi Atsbha ),이철진 한국공업화학회 2023 한국공업화학회 연구논문 초록집 Vol.2023 No.0

패키지형 소형 SCR 시스템 내 NH₃ 농도분포 제어를 위한 AIG의 배치에 관한 전산해석적 연구

박선미(Seon Mi Park),장혁상(Hyuk Sang Chang),조동(Tong Zhao) 大韓環境工學會 2011 대한환경공학회지 Vol.33 No.5

소규모의 대기오염 배출원으로부터 질소산화물을 저감하는 방법으로 제안된 패키지형 SCR (selective catalytic reduction) 시스템 내에서 암모니아 농도제어에 관한 연구가 시행되었다. SCR 시스템의 효율은 촉매층의 효율적인 활용에 좌우되며 촉매층의 효율적인 사용은 시스템에 유입되는 배기가스의 유동균일도와 암모니아 농도의 균일도에 의해 좌우된다. 본 연구에서는 주어진 최적의 유동조건에서 SCR 시스템 내에 배치된 AIG 형상과 분사 유량 조정에 따른 암모니아 농도분포를 평가하였다. 기본 유동조건에서 분사구의 각도에 따른 전산해석 결과, 배가스 유동에 대해 동류방향(0°)으로 암모니아를 분사한 경우의 농도분포의 RMS(%) 수치는 약 95.3%, 대향방향인 120°의 각도를 가지는 경우 90.1%로 파악되어 대향방향으로의 분사가 더 효율적인 것으로 파악되었다. 유동박리영역에서 벗어나도록 분사구의 위치를 변경하고 기초계산에서의 속도분포와 농도분포를 기준으로 환원제 유량을 조정한 결과 RMS(%) 수치를 최대 62.8%까지 하강시키는 효과를 가져왔다. AIG 형상 및 배치구조에 혼합증진의 효과를 정리하였다. A package type of SCR (selective catalytic reduction) system that was proposed for removing the NOx found in flue gas from the small scale of air pollution sources was evaluated. The efficiency of the SCR system is determined by the proper utilization of catalytic media installed inside of the system, and the proper distribution of flow velocity and NH₃ concentration in the flue gas is a crucial factor for using the catalytic media. In this study, the distributions of NH₃ concentration were estimated under the various arrays and shapes of AIG at the given gas flow condition. The value of RMS (%) in NH₃ concentration is 95.3% at co-current flow (at 0°) injection but it is 90.1% at the condition of counter-current flow (at 120°) condition, which implies the counter-current injection is more favorable. By rearranging the NH₃ injection flow rates based on the distribution of velocity and NH₃ distribution in basic calculation, the value of RMS (%) in NH₃ concentration was reduced to 62.8%. The enhanced effect of NH₃ mixing by the combined effect of arrays and shapes are complied in the study.

선박용 디젤엔진 SCR 시스템 요소 기술에 관한 기초 연구

박윤용(Yoon-Yong Park),송하철(Ha-Cheol Son),안기주(Gi-Ju Ah),심천식(Chun-Sik Shim) 한국항해항만학회 2016 한국항해항만학회지 Vol.40 No.4

: 2016년부터 배출통제지역(ECA : Emission Control Atea)을 운항하는 선박에 대하여 배출되는 NOx(질소산화물) 및 SOx(황산화 물)의 배기량 감소규제가 강화되었다. 상기의 규제 물질 중 NOx를 제거하는 탈질장비 중 선택적 촉매 환원(SCR : Selectivity Catalytic Reduction) 시스템은 효율이 높고 상업적으로 많이 활용되고 있으나, 높은 온도에서 요소수가 활성화되는 단점이 있다. 이에 초미세기포를 이 용하여 낮은 온도에서도 반응할 수 있는 요소수 및 요소수 활성화 기기를 개발하여 상기의 문제점들을 최소화 할 수 있도록 하였다. 또한 SCR 시스템의 효율성을 향상시키는 방안을 마련하기 위하여, ANSYS-CFX package를 이용한 전산유체역학(CFD : Computational fluid dynamics)기법을 사용하였다. Navier-Stokes 방정식을 해석의 지배방정식으로 적용하여 SCR 시스템의 점성유동해석 시뮬레이션을 수행하였 다. SCR 시스템의 형상은 CATIA V5를 사용하여 3D 모델링을 하였고, SCR 시스템의 효율성을 비교하기 위해 요소수 분사 노즐의 위치를 요소수 분사 노즐은 배기관의 입구로부터 1/3, 1/2, 2/3로 변경하며 확인하였다. 또한, 노즐의 분사구 수가 SCR 시스템의 효율에 미치는 영향 을 확인하기 위하여 분사구 수가 4, 6, 8개일 경우를 시뮬레이션 하여 비교․분석하였다. 시뮬레이션 결과 배기관 입구에 가까울수록, 분사구 수가 많을수록 효율이 향상됨을 확인하였다. : From 2016, controls on reduction of NOx and SOx emissions from the vessels that are operated in the emission control area were tightened. The selectivity catalytic reduction system of the denitrification equipment which NOx among the above controlled materials is very effective and used commercially very much. But it has the disadvantage that CSR is activated at high temperatures. Therefore, the SCR and SCR activation instrument that can react even at low temperatures by using micro-nano bubbles so that the above problems can be minimized were developed. And the computational fluid dynamics technique was used by ANSYS-CFX package to prepare the plan that improves the SCR system's efficiency. Simulation for the viscous flow analysis of the SCR system was executed by applying the Navier-Stokes equation to it as a governing equation. For the SCR system's shape, 3D modeling was done by using CATIA V5. SCR jet nozzle's position was checked by changing it to the intervals of 1/3, 1/2, and 2/3 from the inlet of the vent pipe to compare the SCR system's efficiency. And the number of nozzles was compared and analyzed by simulating 4, 6, and 8 holes to check an effect of the number on the SCR system's efficiency. The simulation result has found that the closer nozzles are to the inlet of the vent pipe and the more nozzles are, the more efficiency is improved.

SNCR 시스템 내부의 물질 반응에 관한 전산해석적 연구

구성모,유경선,장혁상 한국청정기술학회 2019 청정기술 Vol.25 No.1

Numerical analysis was done to evaluate the chemical reaction and the reduction rate inside of selective non-catalyticreduction to denitrification in combustion process. The NOX reduction in selective non-catalytic reduction is converted to notonly nitrogen but also nitrous oxide. Simultaneous NOX reduction and nitrous oxide generation suppressing is required inselective non-catalytic reduction because nitrous oxide influences the global warming as a greenhouse gas. The current study wasperformed compare the computational analysis in the same temperature and amount of NaOH, and in comparison with theprevious research experiments and confirmed the reliability of the computational fluid dynamics. Additionally, controlling theaddition amount of NaOH to predict the NOX reduction efficiency and nitrous oxide production. Numerical analysis was done tocheck the mass fraction of each material in the measurement point at the end of selective non-catalytic reduction. ExperimentalValue and simulation value by numerical analysis showed an error of up to 18.9% was confirmed that a generally well predicted. and it was confirmed that the widened temperature range of more than 70% NOX removal rate is increased when the additionamount of NaOH. So, large and frequent changes of the reaction temperature waste incineration facilities are expected to be effective. 연소공정 내에서 질소산화물 배출을 저감하는 선택적 무촉매 환원장치 내부의 화학반응 및 저감효율에 대한 수치해석이 실행되었다. 선택적 무촉매 환원장치에서 저감된 질소산화물은 질소뿐만 아니라 아산화질소로도 전환된다. 아산화질소는 온실가스로써 지구온난화에 영향을 끼치기 때문에 선택적 무촉매 환원장치 내의 질소산화물 제어와 동시에 아산화질소 생성제어가 요구되어진다. 본 연구에서는 선행연구에서 실행된 실험과 온도조건과 가성소다의 첨가량이 동일한 선택적 무촉매환원장치 내의 전산해석을 실시하고 비교하여 전산해석의 신뢰성을 확인하고, 가성소다 첨가량을 추가적으로 조절하여 질소산화물의 저감 효율과 아산화질소 생성량을 예측하였다. 전산해석은 후단의 측정점을 설정하여 각 물질의 질량분율을 확인하였다. 세부적으로는 측정점에서 유동방향에 수직한 면을 설정하여 온도 조건과 가성소다 첨가량에 따른 각 물질의 평균 질량분율을 비교하였다. 실험값과 전산해석에 의한 모사값은 최대 18.9%의 오차를 보이며 대체적으로 잘 예측됨을 확인하였으며 가성소다 첨가량을 증가시켰을 땐 70% 이상의 제거율의 온도 범위가 넓어지는 것을 확인하였다. 따라서 반응온도의 낙차가 크고 잦은 폐기물 소각시설 등에서 효과적일 것으로 예상된다.

Thermal and Nonthermal Lattice Gas Models for a Dimer-trimer Surface Catalytic Reaction: A Monte-Carlo Simulation Study

K. Iqbal,Parvaiz A. Khand 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.3

We have studied the kinetics of an irreversible dimer-trimer reaction of the type 2 A_3 + 3 B_2 ! 6 AB by considering the precursor motion of the dimer (B_2) on a square, as well as on a hexagonal surface, by using a Monte Carlo simulation. When the movement of precursors is limited to the first nearest neighborhood, the model gives reactive window widths of the order of 0.22 and 0.29 for the square and the hexagonal lattices, respectively, which are quite large compared to those predicted by the Langmuir-Hinshelwood (LH) model. The phase diagrams resemble qualitatively to those of standard Ziff, Gulari and Barshad (ZGB) model. The width of the reactive window of the precursor model depends upon the mobility of the precursors. The continuous transition disappears when the motion of precursors is extended to the third nearest neighborhood. The diffusion of B atoms to adjacent vacant sites, as well as desorption of the dimer (B_2) from the surface with a certain probability (P), is also considered.