Pub Date : 2009-10-08DOI: 10.1109/APCC.2009.5375585
Guiling Wu, Ming Li, Pan Guo, Xinwan Li, Jianping Chen
A multi-wavelength space multiplexing photonic A/D converters is proposed which combines the WDM and space division multiplexing and enables higher sampling rate with the low loss and completely passive demultiplexing feature. The key technologies and progress are discussed.
{"title":"Multi-wavelength space multiplexing photonic A/D converters","authors":"Guiling Wu, Ming Li, Pan Guo, Xinwan Li, Jianping Chen","doi":"10.1109/APCC.2009.5375585","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375585","url":null,"abstract":"A multi-wavelength space multiplexing photonic A/D converters is proposed which combines the WDM and space division multiplexing and enables higher sampling rate with the low loss and completely passive demultiplexing feature. The key technologies and progress are discussed.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122864813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-10-08DOI: 10.1109/APCC.2009.5375630
Sujun Zhang, J. Ping, Hao-jian Yan, Tingting Han1
Investigations of planetary atmospheres, ionospheres, rings, and magnetic fields using radio science techniques have been conducted by almost every planetary mission, and are planned for many future projects. Changes in the frequency, phase, amplitude and polarization of spacecraft radio signal, caused by passage through the atmosphere and ionosphere of the planet, were observed in rising and descending planet occultation events. Utilizing one inversion method, we can get the refractivity profiles of the atmosphere, density, temperature and pressure profiles of the neutral atmosphere, and the electron density profile of the ionosphere. Principles of the planetary radio occultation technique, physical backgrounds and module specifications of the YH-1 ground-based planetary atmosphere occultation processing system are described in this paper.
{"title":"Planetary radio occultation technique and inversion method for YH-1 Mars mission","authors":"Sujun Zhang, J. Ping, Hao-jian Yan, Tingting Han1","doi":"10.1109/APCC.2009.5375630","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375630","url":null,"abstract":"Investigations of planetary atmospheres, ionospheres, rings, and magnetic fields using radio science techniques have been conducted by almost every planetary mission, and are planned for many future projects. Changes in the frequency, phase, amplitude and polarization of spacecraft radio signal, caused by passage through the atmosphere and ionosphere of the planet, were observed in rising and descending planet occultation events. Utilizing one inversion method, we can get the refractivity profiles of the atmosphere, density, temperature and pressure profiles of the neutral atmosphere, and the electron density profile of the ionosphere. Principles of the planetary radio occultation technique, physical backgrounds and module specifications of the YH-1 ground-based planetary atmosphere occultation processing system are described in this paper.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124288215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-10-08DOI: 10.1109/APCC.2009.5375641
M. Kim, Min-Cheol Hong
The purpose of this paper is to improve allocation of the number of bits without skipping the frame by accurately estimating the target bits in H.264/AVC rate control. In our scheme, we propose an enhancement method of the target frame rate based H.264/AVC bit allocation. The enhancement uses a frame complexity estimation to improve the existing mean absolute difference (MAD) complexity measurement. Bit allocation to each frame is not just computed by target frame rate but also adjusted by a combined frame complexity measure. Using the statistical characteristic, we obtain change of occurrence bit about QP to apply the bit amount by QP from the video characteristic and applied in the estimated bit amount of the current frame. Simulation results show that the proposed rate control scheme achieves time saving of more than 99% over existing rate control algorithm. Nevertheless, PSNR and bit rate were almost same as the performances.
{"title":"Adaptive real-time rate control for H.264","authors":"M. Kim, Min-Cheol Hong","doi":"10.1109/APCC.2009.5375641","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375641","url":null,"abstract":"The purpose of this paper is to improve allocation of the number of bits without skipping the frame by accurately estimating the target bits in H.264/AVC rate control. In our scheme, we propose an enhancement method of the target frame rate based H.264/AVC bit allocation. The enhancement uses a frame complexity estimation to improve the existing mean absolute difference (MAD) complexity measurement. Bit allocation to each frame is not just computed by target frame rate but also adjusted by a combined frame complexity measure. Using the statistical characteristic, we obtain change of occurrence bit about QP to apply the bit amount by QP from the video characteristic and applied in the estimated bit amount of the current frame. Simulation results show that the proposed rate control scheme achieves time saving of more than 99% over existing rate control algorithm. Nevertheless, PSNR and bit rate were almost same as the performances.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125668049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-10-08DOI: 10.1109/APCC.2009.5375577
Y. Tang, X. Hong, X. Cao, Z. Zhao, L. Zhao, W. Wang, J. Wu, J. Lin
Fast tunable wavelength converter based on a GCSR laser and a digital driver is demonstrated in this paper. The wavelength coverage of the GCSR laser is over 40 nm. Hopping-mode wavelengths generated during tuning process are suppressed. Experimental results show that the shortest tuning time is within 6 ns of wavelength coverage 6.6 nm and the suppression ratio of the hopping-mode is 40 dB.
{"title":"Fast tunable wavelength converter with hopping-mode suppression based on GCSR laser and fine digital driver","authors":"Y. Tang, X. Hong, X. Cao, Z. Zhao, L. Zhao, W. Wang, J. Wu, J. Lin","doi":"10.1109/APCC.2009.5375577","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375577","url":null,"abstract":"Fast tunable wavelength converter based on a GCSR laser and a digital driver is demonstrated in this paper. The wavelength coverage of the GCSR laser is over 40 nm. Hopping-mode wavelengths generated during tuning process are suppressed. Experimental results show that the shortest tuning time is within 6 ns of wavelength coverage 6.6 nm and the suppression ratio of the hopping-mode is 40 dB.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130273790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-10-08DOI: 10.1109/APCC.2009.5375469
Yi-Mao Hsiao, Ming-Jen Chen, Yu-Jen Hsiao, Hui-Kai Su, Y. Chu
With the rapid development of the Internet applications and the explosion of end users, IP address has been exhausted and routing lookup speed is the bottleneck of router design. In addition TCAM is widely used for implementation fast IP forwarding table lookup. However, the need to maintain a sorted list incremental updates may slow the lookup speed in a TCAM. In this paper, a fast TCAM update scheme is proposed for TCAM-Based IPv6 routing lookup architecture. Based on the characteristic of prefix distribution, we design a TCAM-Based router architecture for IPv6 routing lookup. As simulation result shows more than 90% update do not need any memory movement in updating operation. The worse case is (D-2)/2, where D is the length of chain.
{"title":"A fast update scheme for TCAM-based IPv6 routing lookup architecture","authors":"Yi-Mao Hsiao, Ming-Jen Chen, Yu-Jen Hsiao, Hui-Kai Su, Y. Chu","doi":"10.1109/APCC.2009.5375469","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375469","url":null,"abstract":"With the rapid development of the Internet applications and the explosion of end users, IP address has been exhausted and routing lookup speed is the bottleneck of router design. In addition TCAM is widely used for implementation fast IP forwarding table lookup. However, the need to maintain a sorted list incremental updates may slow the lookup speed in a TCAM. In this paper, a fast TCAM update scheme is proposed for TCAM-Based IPv6 routing lookup architecture. Based on the characteristic of prefix distribution, we design a TCAM-Based router architecture for IPv6 routing lookup. As simulation result shows more than 90% update do not need any memory movement in updating operation. The worse case is (D-2)/2, where D is the length of chain.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124667448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-10-08DOI: 10.1109/APCC.2009.5375501
K. Nakajima, K. Mase, Hiraku Okada
In a wireless mesh network (WMN) connected to the outer infrastructure such as the Internet, one or more gateways to connect to the outer network as well as surrounding nodes may frequently be congested by concentration of traffic from mobile stations. To resolve the congestion, we propose a new congestion control scheme for layer 3 WMNs. In the proposed scheme, nodes composing WMN backbone (MNs: mesh nodes) monitor their transmission queue periodically and detect congestion. When an MN detects congestion, it identifies MNs which inject a dominant amount of traffic causing congestion, and sends a congestion control message to these MNs. When the MNs receive the congestion control message, they control the bandwidth of the traffic toward the congested MN. We have performed simulation of the proposed scheme using a simple network model and evaluated the effect of congestion control. We have shown that the proposed method is effective to reduce average queue length of the bottle-neck MN and to improve the total throughput significantly.
{"title":"A congestion control scheme for layer 3 wireless mesh networks","authors":"K. Nakajima, K. Mase, Hiraku Okada","doi":"10.1109/APCC.2009.5375501","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375501","url":null,"abstract":"In a wireless mesh network (WMN) connected to the outer infrastructure such as the Internet, one or more gateways to connect to the outer network as well as surrounding nodes may frequently be congested by concentration of traffic from mobile stations. To resolve the congestion, we propose a new congestion control scheme for layer 3 WMNs. In the proposed scheme, nodes composing WMN backbone (MNs: mesh nodes) monitor their transmission queue periodically and detect congestion. When an MN detects congestion, it identifies MNs which inject a dominant amount of traffic causing congestion, and sends a congestion control message to these MNs. When the MNs receive the congestion control message, they control the bandwidth of the traffic toward the congested MN. We have performed simulation of the proposed scheme using a simple network model and evaluated the effect of congestion control. We have shown that the proposed method is effective to reduce average queue length of the bottle-neck MN and to improve the total throughput significantly.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125000697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-10-08DOI: 10.1109/APCC.2009.5375664
Kazuki Takeda, F. Adachi
The bit error rate (BER) performance improvement of single-carrier signal transmissions using one-tap frequency-domain pre-equalization (pre-FDE) is limited by the residual inter-symbol interference (ISI). Recently, we proposed a joint Tomlinson-Harashima precoding (THP) and pre-FDE (called joint THP/pre-FDE) to improve the BER performance by removing the residual ISI. In this paper, to further improve the BER performance, we optimize THP based on the minimum mean square error (MMSE) criterion and propose a joint MMSE-THP/pre-FDE. The achievable BER and throughput are evaluated by computer simulation.
{"title":"Performance of joint MMSE-THP/Pre-FDE for single-carrier transmissions in a frequency-selective channel","authors":"Kazuki Takeda, F. Adachi","doi":"10.1109/APCC.2009.5375664","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375664","url":null,"abstract":"The bit error rate (BER) performance improvement of single-carrier signal transmissions using one-tap frequency-domain pre-equalization (pre-FDE) is limited by the residual inter-symbol interference (ISI). Recently, we proposed a joint Tomlinson-Harashima precoding (THP) and pre-FDE (called joint THP/pre-FDE) to improve the BER performance by removing the residual ISI. In this paper, to further improve the BER performance, we optimize THP based on the minimum mean square error (MMSE) criterion and propose a joint MMSE-THP/pre-FDE. The achievable BER and throughput are evaluated by computer simulation.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126786650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-10-08DOI: 10.1109/APCC.2009.5375609
J. Oliver, R. Aravind, K. Prabhu
We consider the problem of pilot-aided accurate least squares (LS) channel estimation in the presence of carrier frequency offset (CFO). We first formulate the mean square error (MSE) of the LS channel estimator in the presence of CFO and then show how to select the pilot sequence (with element values constrained to plus or minus one) that minimizes the MSE. Our main conclusion is that, in the presence of CFO accurate channel estimates can be obtained by transmitting identical pilot symbol on all subcarriers. We demonstrate our results via computer simulations.
{"title":"Improved channel estimation in OFDM systems in the presence of CFO","authors":"J. Oliver, R. Aravind, K. Prabhu","doi":"10.1109/APCC.2009.5375609","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375609","url":null,"abstract":"We consider the problem of pilot-aided accurate least squares (LS) channel estimation in the presence of carrier frequency offset (CFO). We first formulate the mean square error (MSE) of the LS channel estimator in the presence of CFO and then show how to select the pilot sequence (with element values constrained to plus or minus one) that minimizes the MSE. Our main conclusion is that, in the presence of CFO accurate channel estimates can be obtained by transmitting identical pilot symbol on all subcarriers. We demonstrate our results via computer simulations.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"122 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127971658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-10-08DOI: 10.1109/APCC.2009.5375517
Jaewoo Kim, Hyunduk Jung, Jaiyong Lee
Network Mobility (NEMO) supports the movement of some part of the network that a group of the Mobile Nodes (MNs) or the Mobile Routers (MRs) moves together. To support NEMO, the NEMO basic support protocol (NBSP) was proposed [1]. In the nested mobile network, however, the NBSP exhibits pinball routing problem. As the degree of nesting increase, the problem becomes more serious. In this paper, we propose a new NEMO management scheme using Tree-based Care of Address (TCoA) and Mobile Network Prefix (MNP). In proposed scheme, all the MRs belonging to the Root-MR in the nested mobile network configure their care-of addresses (CoA) based on the MNP of Root-MR. It mitigates the pinball routing problem. Performance analysis indicates that proposed scheme can reduce end-to-end packet delay and handoff delay.
NEMO (Network Mobility)是指一组移动节点(MNs)或移动路由器(MRs)一起移动网络的一部分。为了支持NEMO，提出了NEMO基本支持协议(NEMO basic support protocol, NBSP)[1]。然而，在嵌套移动网络中，NBSP存在弹球路由问题。随着嵌套程度的增加，问题变得更加严重。在本文中，我们提出了一种新的NEMO管理方案，使用基于树的地址保护(TCoA)和移动网络前缀(MNP)。在该方案中，在嵌套移动网络中，所有属于Root-MR的MRs都基于Root-MR的MNP来配置它们的照顾地址(CoA)。它减轻了弹球路由问题。性能分析表明，该方案可以降低端到端数据包延迟和切换延迟。
{"title":"Route optimization for network mobility with tree-based care of address","authors":"Jaewoo Kim, Hyunduk Jung, Jaiyong Lee","doi":"10.1109/APCC.2009.5375517","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375517","url":null,"abstract":"Network Mobility (NEMO) supports the movement of some part of the network that a group of the Mobile Nodes (MNs) or the Mobile Routers (MRs) moves together. To support NEMO, the NEMO basic support protocol (NBSP) was proposed [1]. In the nested mobile network, however, the NBSP exhibits pinball routing problem. As the degree of nesting increase, the problem becomes more serious. In this paper, we propose a new NEMO management scheme using Tree-based Care of Address (TCoA) and Mobile Network Prefix (MNP). In proposed scheme, all the MRs belonging to the Root-MR in the nested mobile network configure their care-of addresses (CoA) based on the MNP of Root-MR. It mitigates the pinball routing problem. Performance analysis indicates that proposed scheme can reduce end-to-end packet delay and handoff delay.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129062466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-10-08DOI: 10.1109/APCC.2009.5375467
Y. Fukushima, Kazuya Inada, Y. Tao, Yasuyuki Fujiwara, T. Yokohira
In this paper, we evaluate the performance of peer selection algorithms: MLH (Minimum Logical Hop) and MPH (Minimum Physical Hop) to increase the number of joining peers and to decrease inter-AS traffic volume in P2P live streaming, where we assume that every peer's logical hop count (the number of providing peers between an origin streaming server and the peer) is limited by a predetermined value in order to keep real-time property of live streaming. In MLH, a newly joining peer selects such providing peers that the logical hop count is minimum to increase the number of joining peers. And then if there are several such providing peers, the newly joining peer selects such providing peers that the number (physical hop count) of ASs between the newly joining peer and each of the providing peers is minimum to decrease the inter-AS traffic volume. In MPH, a newly joining peer selects providing peers in the reverse order of MLH. Simulation results show that MLH achieves about from 20% to 60% more maximum joining peers than MPH, and MPH shows smaller inter-AS traffic volume than MLH when the number of joining peers is small while MLH shows smaller inter-AS traffic volume when the number of joining peers is large.
{"title":"Performance evaluation of as-friendly peer selection algorithms for P2P live streaming","authors":"Y. Fukushima, Kazuya Inada, Y. Tao, Yasuyuki Fujiwara, T. Yokohira","doi":"10.1109/APCC.2009.5375467","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375467","url":null,"abstract":"In this paper, we evaluate the performance of peer selection algorithms: MLH (Minimum Logical Hop) and MPH (Minimum Physical Hop) to increase the number of joining peers and to decrease inter-AS traffic volume in P2P live streaming, where we assume that every peer's logical hop count (the number of providing peers between an origin streaming server and the peer) is limited by a predetermined value in order to keep real-time property of live streaming. In MLH, a newly joining peer selects such providing peers that the logical hop count is minimum to increase the number of joining peers. And then if there are several such providing peers, the newly joining peer selects such providing peers that the number (physical hop count) of ASs between the newly joining peer and each of the providing peers is minimum to decrease the inter-AS traffic volume. In MPH, a newly joining peer selects providing peers in the reverse order of MLH. Simulation results show that MLH achieves about from 20% to 60% more maximum joining peers than MPH, and MPH shows smaller inter-AS traffic volume than MLH when the number of joining peers is small while MLH shows smaller inter-AS traffic volume when the number of joining peers is large.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131446414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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