An IMS based Inter-Working Solution for Multimedia Service in a Converged Network

Zhongwen Zhu 보안공학연구지원센터 2008 International Journal of Multimedia and Ubiquitous Vol.3 No.4

In the evolution of traditional telecom network towards a converged next generation network, Inter-working is always challenging due to different name spaces and routing mechanism across different communities. Most existing Inter-working solutions are terminal based solutions. They require mobile phone or PC users to install multiple client-side applications on the devices, such as, Google talk client, Skype client, and MSN client, etc. In order to avoid too many client applications running on mobile terminals that normally have a limited resource, a network based Inter-working solution is desired. An IMS based Inter-working solution for multi-media services is proposed. It enables an IMS subscriber make use of a single SIP user agent to communicate with the other users who might have communication means other than IMS based devices. The solution consists of two parts in the network: one is the conference like service that resides at the originating side and provides “forking service”; the other is the Inter-working gateway service that provides the protocol conversion service. The detailed technical description of the proposed solution is described hereafter. The corresponding use cases are studied. The application of the solution to the Group Communication service, e.g. an ad-hoc group or pre-defined group multimedia service, is also discussed. The benefits of the proposed solution for end users and operators are highlighted respectively.

Analysis of Multi-Agent-Based Adaptive Droop-Controlled AC Microgrids with PSCAD

Zhongwen Li,Chuanzhi Zang,Peng Zeng,Haibin Yu,Hepeng Li,Shuhui Li 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2

A microgrid (MG) with integrated renewable energy resources can benefit both utility companies and customers. As a result, they are attracting a great deal of attention. The control of a MG is very important for the stable operation of a MG. The droop-control method is popular since it avoids circulating currents among the converters without using any critical communication between them. Traditional droop control methods have the drawback of an inherent trade-off between power sharing and voltage and frequency regulation. An adaptive droop control method is proposed, which can operate in both the island mode and the grid-connected mode. It can also ensure smooth switching between these two modes. Furthermore, the voltage and frequency of a MG can be restored by using the proposed droop controller. Meanwhile, the active power can be dispatched appropriately in both operating modes based on the capacity or running cost of the Distributed Generators (DGs). The global information (such as the average voltage and output active power of the MG and so on) required by the proposed droop control method to restore the voltage and frequency deviations can be acquired distributedly based on the Multi Agent System (MAS). Simulation studies in PSCAD demonstrate the effectiveness of the proposed control method.

Integrative applications of network pharmacology and molecular docking: An herbal formula ameliorates H9c2 cells injury through pyroptosis

Zhongwen Qi,Zhipeng Yan,Yueyao Wang,Nan Ji,Xiaoya Yang,Ao Zhang,Meng Li,Fengqin Xu,Junping Zhang The Korean Society of Ginseng 2023 Journal of Ginseng Research Vol.47 No.2

Background: QiShen YiQi pills (QSYQ) is a Traditional Chinese Medicine (TCM) formula, which has a significant effect on the treatment of patients with myocardial infarction (MI) in clinical practice. However, the molecular mechanism of QSYQ regulation pyroptosis after MI is still not fully known. Hence, this study was designed to reveal the mechanism of the active ingredient in QSYQ. Methods: Integrated approach of network pharmacology and molecular docking, were conducted to screen active components and corresponding common target genes of QSYQ in intervening pyroptosis after MI. Subsequently, STRING and Cytoscape were applied to construct a PPI network, and obtain candidate active compounds. Molecular docking was performed to verify the binding ability of candidate components to pyroptosis proteins and oxygen-glucose deprivation (OGD) induced cardiomyocytes injuries were applied to explore the protective effect and mechanism of the candidate drug. Results: Two drug-likeness compounds were preliminarily selected, and the binding capacity between Ginsenoside Rh2 (Rh2) and key target High Mobility Group Box 1 (HMGB1)was validated in the form of hydrogen bonding. 2 μM Rh2 prevented OGD-induced H9c2 death and reduced IL-18 and IL-1β levels, possibly by decreasing the activation of the NLRP3 inflammasome, inhibiting the expression of p12-caspase1, and attenuating the level of pyroptosis executive protein GSDMD-N. Conclusions: We propose that Rh2 of QSYQ can protect myocardial cells partially by ameliorating pyroptosis, which seems to have a new insight regarding the therapeutic potential for MI.

Seismic performance of L-shaped RC walls sustaining Unsymmetrical bending

Zhongwen Zhang,Bing Li 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.78 No.3

Reinforced concrete (RC) structural walls with L-shaped sections are commonly used in RC buildings. The walls are often expected to sustain biaxial load and Unsymmetrical bending in an earthquake event. However, there currently exists limited experimental evidence regarding their seismic behaviour in these lateral loading directions. This paper makes experimental and numerical investigations to these walls behaviours. Experimental evidences are presented for four L-shaped wall specimens which were tested under simulated seismic load from different lateral directions. The results highlighted some distinct behaviour of L-shaped walls sustaining Unsymmetrical bending relating to their seismic performance. First, due to the Unsymmetrical bending, out-of-plane reaction forces occur for these walls, which contribute to accumulation of the out-of-plane deformations of the wall, especially when out-of-plane stiffness of the section is reduced by horizontal cracks in the cyclic load. Secondly, cracking was found to affect shear centre of the specimens loaded in the Unsymmetrical bending direction. The shear centre of these specimens distinctly differs in the flange in the positive and negative loading direction. Cracking of the flange also causes significant warping in the bottom part of the wall, which eventually lead to out-of-plane buckling failure.

Adaptive Chaotic Gray Wolf Optimizer-Based Optimization of Decentralized AGC and Power Dispatching Controllers for Integrated Energy System with Heterogeneous Power Sources

Li Zhongwen,Bai Ningning,Cheng Zhiping,Wang Yi,Si Jikai 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.2

With the increasing use of renewable energy sources connected to inverters in modern power systems, traditional units’ rotary inertia and frequency regulation capacity are becoming inadequate. Therefore, exploring various types of frequency regulation resources is essential. However, these resources come with diferent system models, capacities, and response speeds, posing a signifcant challenge to automatic generation control (AGC). To address this issue and enhance the frequency regulation performance of these resources, a novel distributed coordination AGC method is proposed. The proposed method allows each frequency regulation unit to utilize a separate load frequency control (LFC) controller to participate in frequency regulation based on the area control error information calculated by the dispatching center. To ensure the coordination between the heterogeneous frequency regulation resources, an adaptive chaotic gray wolf algorithm is proposed to tune the parameters of the LFC controller. Furthermore, to release the fast frequency regulation ability of high-speed frequency regulation units and better prepare for the next round of frequency regulation service, an event-triggered power dispatching strategy is proposed. Simulation results of a single-area power system with fve diferent frequency regulation units demonstrate the superior performance of the proposed AGC method.

Analysis of Multi-Agent-Based Adaptive Droop-Controlled AC Microgrids with PSCAD: Modeling and Simulation

Li, Zhongwen,Zang, Chuanzhi,Zeng, Peng,Yu, Haibin,Li, Hepeng,Li, Shuhui The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2

A microgrid (MG) with integrated renewable energy resources can benefit both utility companies and customers. As a result, they are attracting a great deal of attention. The control of a MG is very important for the stable operation of a MG. The droop-control method is popular since it avoids circulating currents among the converters without using any critical communication between them. Traditional droop control methods have the drawback of an inherent trade-off between power sharing and voltage and frequency regulation. An adaptive droop control method is proposed, which can operate in both the island mode and the grid-connected mode. It can also ensure smooth switching between these two modes. Furthermore, the voltage and frequency of a MG can be restored by using the proposed droop controller. Meanwhile, the active power can be dispatched appropriately in both operating modes based on the capacity or running cost of the Distributed Generators (DGs). The global information (such as the average voltage and output active power of the MG and so on) required by the proposed droop control method to restore the voltage and frequency deviations can be acquired distributedly based on the Multi Agent System (MAS). Simulation studies in PSCAD demonstrate the effectiveness of the proposed control method.

Correction: Adaptive Chaotic Gray Wolf Optimizer-Based Optimization of Decentralized AGC and Power Dispatching Controllers for Integrated Energy System with Heterogeneous Power Sources

Li Zhongwen,Bai Ningning,Cheng Zhiping,Wang Yi,Si Jikai 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.3

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Posters ( 1998 . 11 . 12 - 17 ) : Anti - tumor Constituents from Isodon xerophilus

(Aijun HOU Zhongwen LIN),(Handong SUN) 한국응용약물학회 1998 학술대회 Vol.1998 No.1

Research on Data Heterogeneity in Enterprise Information Integration

Ruizhen Duan,Zhongwen Wang,Mingshan Chi,Xiaoqiu Xu 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.3

In view of the problem of data heterogeneity in enterprise application integration, we proposed a solution, which is based on XML, WSDL and Web Service technology to achieve the elimination of data heterogeneity, which can reduce the complexity of the system, and has certain significance for the information communication between enterprises and enterprises.

Moment redistribution of RC continuous beams: Re-examination of code provisions

Da Luo,Zhongwen Zhang,Bing Li 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.85 No.5

Many codes allow designers to use the bending moment diagram computed by elastic analysis and modify it by a certain amount of moment redistribution (MR) to account for plastic behaviour of continuous beams. However, several researchers indicated that the MR at the ultimate limit state (u) for some beams deviate significantly from the specified values of various codes. This paper examines the applicability of the provisions on u in ACI 318-19 and Eurocode 2 through numerical investigations and comprehensively explores the influencing factors. The results show that some parameters not considered in those codes influence u to a certain extent, where the ratio of tensile reinforcement ratio at intermediate support to tensile reinforcement ratio at midspan (s1/s2) and load type are crucial parameters to consider. The specific combination of these two parameters may make the codes overestimate or significantly underestimate the u. On the other hand, the yield state of both critical sections is found to have an important influence on the influence degree of each parameter on u. The yield conditions are investigated, and an empirical judgment equation is proposed. In addition, the influence laws of the critical parameters on u have been further proved by theoretical derivation. Finally, due to t is found to have a better linear correlation with βu than xu/d, equations as a function of t for predicting the u of continuous beams under the two loads are proposed, respectively.