Temporal Information Services in Large-Scale Vehicular Networks Through Evolutionary Multi-Objective Optimization

Dai, Penglin,Liu, Kai,Feng, Liang,Zhang, Haijun,Lee, Victor Chung Sing,Son, Sang Hyuk,Wu, Xiao IEEE 2019 IEEE transactions on intelligent transportation sy Vol.20 No.1

<P>Temporal information services are critical in implementing emerging intelligent transportation systems. Nevertheless, it is challenging to realize timely temporal data update and dissemination due to an intermittent wireless connection and a limited communication bandwidth in dynamic vehicular networks. Some previous studies have considered the temporal data dissemination in vehicular networks, but they are limited to the service region, which is inside the coverage of roadside units. To enhance system scalability, it is imperative to exploit the synergic effect of vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) communications for providing efficient temporal information services in such an environment. With the above motivations, we propose a novel system architecture to enable efficient data scheduling in hybrid V2I/V2V communications by having the global knowledge of network resources of the system. On this basis, we formulate a temporal data upload and dissemination (<I>TDUD</I>) problem, aiming at optimizing two conflict objectives simultaneously, which are enhancing the data quality and improving the delivery ratio. Furthermore, we propose an evolutionary multi-objective algorithm called <I>MO-TDUD</I>, which consists of a decomposition scheme for handling multiple objectives, a scalable chromosome representation for <I>TDUD</I> solution encoding, and an evolutionary operator designed for <I>TDUD</I> solution reproduction. The proposed <I>MO-TDUD</I> can be adaptive to different requirements on data quality and delivery ratio by selecting the best solution from the derived Pareto solutions. Last but not least, we build the simulation model and implement <I>MO-TDUD</I> for performance evaluation. The comprehensive simulation results demonstrate the superiority of the proposed solution.</P>

Bandwidth Efficiency and Service Adaptiveness Oriented Data Dissemination in Heterogeneous Vehicular Networks

Dai, Penglin,Liu, Kai,Wu, Xiao,Liao, Yong,Lee, Victor Chung Sing,Son, Sang Hyuk IEEE 2018 IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY Vol.67 No.7

<P>Heterogeneous network resources are expected to cooperate with each other to support efficient data services in vehicular networks. However, current data scheduling methods cannot efficiently exploit the benefit of heterogeneous wireless communication interfaces in vehicular networks. In this paper, we propose a software-defined network based service architecture, which enables the scheduler to manage heterogeneous network resources in a centralized way. We analyze the heterogeneity of both data items and networks in terms of data sizes and network features (e.g., cost, transmission rate, coverage, etc.), respectively. On this basis, we formulate a data broadcast and network interface selection (DBNIS) problem, which aims to minimize both the service delay and the network access cost. To tackle the problem efficiently, we propose a coding-assisted multiobjective evolutionary algorithm (CMOEA), which consists of two components: packet encoding and network interface selection. Specifically, for packet encoding, we first develop a packet-size based random linear encoding (PRLE) technique to improve bandwidth efficiency. Then, we theoretically analyze the performance bound of PRLE. For network interface selection, we propose a multiobjective algorithm for network interface selection to adaptively satisfy dynamic requirements with respect to service delay and network access cost by deriving a set of pareto-solutions. Finally, we build the simulation model and implement CMOEA for performance evaluation. The comprehensive simulation results demonstrate the superiority of CMOEA under a wide range of scenarios.</P>

Corrigendum to “Adaptive scheduling for real-time and temporal information services in vehicular networks” [Transport. Res. Part C 71 (2016) 313–332]

Dai, Penglin,Liu, Kai,Feng, Liang,Zhuge, Qingfeng,Lee, Victor C.S.,Son, Sang H. Elsevier 2017 Transportation research. Part C, Emerging technolo Vol.75 No.-

Coding-Assisted Broadcast Scheduling via Memetic Computing in SDN-Based Vehicular Networks

Liu, Kai,Feng, Liang,Dai, Penglin,Lee, Victor C. S.,Son, Sang Hyuk,Cao, Jiannong IEEE 2018 IEEE transactions on intelligent transportation sy Vol.19 No.8

<P>This paper embarks the first study on exploiting the synergy between vehicular caching and network coding for enhancing the bandwidth efficiency of data broadcasting in heterogeneous vehicular networks by presenting a service architecture that exercises the software defined network concept. In particular, we consider the scenario where vehicles request a set of information and they could be served via heterogeneous wireless interfaces, such as roadside units and base stations (BSs). We formulate a novel problem of coding-assisted broadcast scheduling (CBS), aiming at maximizing the broadcast efficiency for the limited BS bandwidth by exploring the synergistic effect between vehicular caching and network coding. We prove the NP-hardness of the CBS problem by constructing a polynomial-time reduction from the simultaneous matrix completion problem. To efficiently solve the CBS problem, we employ memetic computing, which is a nature inspired computational paradigm for tackling complex problems. Specifically, we propose a memetic algorithm, which consists of a binary vector representation for encoding solutions, a fitness function for solution evaluation, a set of operators for offspring generation, a local search method for solution enhancement, and a repair operator for fixing infeasible solutions. Finally, we build the simulation model and give a comprehensive performance evaluation to demonstrate the superiority of the proposed solution.</P>

Prognostic Value of MGMT Promoter Methylation and TP53 Mutation in Glioblastomas Depends on IDH1 Mutation

Wang, Kai,Wang, Yin-Yan,Ma, Jun,Wang, Jiang-Fei,Li, Shao-Wu,Jiang, Tao,Dai, Jian-Ping Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.24

Several molecular markers have been proposed as predictors of outcome in patients with glioblastomas. We investigated the prognostic significance of $O^6$-methylguanine-DNA methyltransferase (MGMT) promoter methylation and TP53 mutation status dependent on isocitrate dehydrogenase 1 (IDH1) mutation in glioblastoma patients. A cohort of 78 patients with histologically confirmed glioblastomas treated with radiation therapy and chemotherapy were reviewed retrospectively. We evaluated the prognostic value of MGMT promoter methylation and TP53 mutation status with regard to progression-free survival (PFS) and overall survival (OS). It was revealed that mutations in IDH1, promoter methylation of MGMT, TP53 mutation, age, Karnofsky performance status (KFS), and extension of resection were independent prognostic factors. In patients with an IDH1 mutation, those with an MGMT methylation were associated with longer PFS (p=0.016) and OS (p=0.013). Nevertheless, the presence of TP53 mutation could stratify the PFS and OS of patients with IDH1 wild type (p=0.003 and 0.029 respectively, log-rank). The MGMT promoter methylation and TP53 mutation were associated with a favorable outcome of patients with and without mutant IDH1, respectively. The results indicate that glioblastomas with MGMT methylation or TP53 mutations have improved survival that may be influenced by IDH1 mutation status.

Modeling and Analysis of CM Noise Behaviors of Transformers in Power Converters

Fu Kai-Ning,Dai Lin-Shan,Lan Wei 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.1

In isolated power converters, electromagnetic feld coupling inside the transformer signifcantly afects its conducted common mode (CM) characteristics. Special concern must be focused on the sophisticated efects of electromagnetic felds on the high-frequency conducted CM noise behaviors of the transformer. The efective frequency range of the existing transformer CM characteristic modeling approaches cannot cover the frequency range from 150 kHz to 30 MHz. Accurately predicting the high frequency conducted CM behavior of transformers is necessary for electromagnetic compatibility design, which avoids the use of unnecessary time in trial and error. In this paper, the scattering parameter is introduced to investigate the high-frequency CM noise behaviors and conducted mechanism of transformers by fnite element method (FEM) simulation tool, and the sensitive factors generating CM noise and causing nonlinear behaviors in the high-frequency range are determined. Good agreement is achieved between FEM simulation results and the measurement in the range of 150 kHz–30 MHz. The proposed simulation modeling method can accurately predict the electric and magnetic feld distribution variation with frequency inside transformer winding window in the design stage, then the high frequency conducted CM noise behavior can also be efectively predicted.

Effect of Vanadium on the Microstructure and Mechanical Properties of 2100 MPa Ultra-High Strength High Plasticity Spring Steel Processed by a Novel Online Rapid-Induction Heat Treatment

Qi‑Lei Dai,Kun Li,Kai‑Ren Meng,Zhou Fang,Wen Chen,Tian‑Bao Yang,Chi Feng,Jin‑Ming Wu,R. D. K. Misra 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.4

Advanced automotive industries generate large demand for the next generation of high strength and high toughness springsteels. Vanadium-containing 55SiCrV spring steels subjected to rapid-induction heating treatment can fulfil such requirements. However, the effect of vanadium microalloying under online rapid-induction heat treatments is rarely reported. Acomparative study of the microstructure and tensile properties of 55SiCr and 55SiCrV spring steel wires subjected to a novelonline rapid induction heat treatment has been demonstrated herein. It is found that the tensile strength of the 55SiCr springwire decreases with the decrease in the wire speed in online rapid-induction heating, and the plasticity increases. Whereas,the tensile strength of the 55SiCrV steel wire increases with the decrease in the wire speed with the retained high plasticity,which is attributed to the strengthening effect of the dislocations. Through the optimized rapid-induction heating/coolingthermal cycles and intermediate-temperature tempering treatment, the tensile strength of the 55SiCrV steel wire approaches2106 MPa with total elongation of 9.7%. Compared with the 55SiCr spring steel, the addition of V in 55SiCrV spring steelchanges the strengthening and toughening mechanisms via the grain refinement and enhancement in the hardenability andtempering resistance. The finely dispersed V-containing secondary phases are rarely found in the matrix, which indicates thatthe precipitation effect stemming from the addition of V is not the dominant strengthening factor in the online rapid-inductionheat process. The proposed novel online rapid-induction heat treatment provides a promising pathway for the mechanicalproperty improvement of the spring steel.

Nonlinear dynamics of a two-stage planetary gear system with sliding friction and elastic continuum ring gear

Wei Liu,Kai Shi,Valerii Tupolev,Guangbin Yu,Bing Dai 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.1

In this paper, nonlinear dynamics of two-stage planetary gear (TSPG) system with elastic ring gear and sliding friction are studied to extend previous study. Compared with the present literatures, the majority of previous works modeled ring gear as a rigid body and completely ignored the sliding friction. This study mainly focus on the investigation of the effect of sliding friction and ring’s elasticity on the nonlinear behavior through the previous elastic TSPG model. Time-varying mesh stiffness formulas including sliding friction and nonlinearity backlash are derived to compare the bifurcation diagrams and vibration response. Numerical examples show interesting behaviors for the TSPG model including sliding friction and elastic component in comparison with the lumped parameter model.

Fluctuating wind and wave simulations and its application in structural analysis of a semi-submersible offshore platform

Jin Ma,Dai Zhou,Zhaolong Han,Kai Zhang,Yan Bao,Li Dong 대한조선학회 2019 International Journal of Naval Architecture and Oc Vol.11 No.1

A semi-submersible offshore platform always operates under complex weather conditions, especially wind and waves. It is vital to analyze the structural dynamic responses of the platform in short-term sea states under the combined wind and wave loads, which touches upon three following work. Firstly, a derived relationship between wind and waves reveals a correlation of wind velocity and significant wave height. Then, an Improved Mixture Simulation (IMS) method is proposed to simulate the time series of wind/waves accurately and efficiently. Thus, a wind-wave scatter diagram is expanded from the traditional wave scatter diagram. Finally, the time series of wind/wave pressures on the platform in the shortterm sea states are converted by Workbench-AQWA. The numerical results demonstrate that the proposed numerical methods are validated to be applicable for wind and wave simulations in structural analyses. The structural dynamic responses of the platform members increase with the wind and wave strength. In the up-wind and wave state, the stresses on the deck, the connections between deck and columns, and the connection between columns and pontoons are relatively larger under the vertical bending moment. These numerical methods and results are wished to provide some references for structural design and health monitoring of several offshore platforms.

Structural Design of High-Rise Building in Toranomon-Azabudai Project (A Block)

Kazumasa, Okabe,Kai, Toyama,Takuya, Furuta,Jyunichi, Yamashita,Hiroki, Mukai,Takahiro, Goseki,Shingo, Masuda,Dai, Shimazaki,Yusuke, Miyagi,Yuji, Ozawa Council on Tall Building and Urban Habitat Korea 2022 International journal of high-rise buildings Vol.11 No.3

This paper explains about structural planning and structural design of the high-rise building in Toranomon-Azabudai Project (A Block) which is now under construction. The building is about 330 meters high, has 4.2 aspect ratio, and the outline of the building has shallow curve. We adopted seismic response control structure. The building is a steel rigid frame structure with braces, and it has enough stiffness to obtain its primary natural period to be less than about seven seconds, in consideration of wind response, seismic response and inhabitability for the wind shaking. In terms of business continuity plan, the building has a high seismic performance; value of story drift angle shall be 1/150 or less and members of the building remain almost undamaged while or after a large earthquake. Active mass dumper shall be installed at the top of the building to improve inhabitability while strong wind is blowing.