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--2018清华大学计算机系篇

获奖名单

2018人民网奖学金获奖名单:
邓理睿、孙晓晴
2018人民网优秀论文获奖者名单:
一等奖:吴成磊;贾许亚;何东标;李峻峰
二等奖:马腾

往年奖学金获奖论文回顾:

2017清华计算机系篇
2016清华计算机系篇
2015清华计算机系篇
2014清华计算机系篇
2013清华计算机系篇
2012清华计算机系篇

优秀论文一等奖(4)

吴成磊

基于主动视场预测的全景视频传输优化
为了缓解全景视频传输所需的巨量的带宽需求,基于切片 (tiling)的传输解决方案将equirectangular 格式的全景视频切分成若干个小块(tile),用于单独编码和传输,以便用户充分利用有限的带宽,选择性地下载覆盖用户视场(field of view,FOV)所需的视频块。然而以前的方法并没有解决如何从服务器向客户端有效传送全景视频切片的问题,其中主要存在两个主要问 题:i)无法预测长期,较远未来的用户的视场,导致无法预取切片以应对网络状况波动不稳定ii)基于瞬时运动状态的视场预测不准确,无法处理随机和快速的头部运动。 本文提出了一个注意力驱动的预取框架来回答这些问题。本文首先搜集了用户观看全景视频时的用户行为数据集,进行了全景视频中用户注意力模型的测量实验,针对用户注意力在观看不同视频内容时存在的不同行为模式,我们提出了一个基于主动长期和短期视场预测的全景视频预取方案。我们重新设计显著性预测网络RMDN,利用深度学习网络的时空视觉偏好提取和循环预测能力来实现高达 10 秒的长期视场预测,并且采用并微调了一个卡尔曼滤波器来提高基于速度的短期视场预测的准确性。为了结合基于深度学习的长期预测和基于去噪后的运动状态的短期预测,我们将预取过程建模为有限状态机,设计了一个自适应的预测策略,以便在切片预取期间实现联合的 “长期-短期” 联合预取以及简化的异常处理,达到高效利用可用带宽,实现提供高 QoS 流的同时,最小化切片缺失率。模拟实验验证了设计的有效性:与传统解决方案相比,本文的系统节省了高达 74.9% 的带宽,同时保持切片缺失率低于 4.5%。
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贾许亚

Intelligent path control for energy-saving in hybrid SDN networks
As power consumption of the internet has been growing quickly in recent years, saving energy has be- come an important problem of networking research. Software-Defined Networking (SDN) brings excellent opportunities to improve network performance and reduce energy consumption by flexible centralized control. However, due to budget constraints and technique limitations, ISPs can upgrade only a limited number of conventional switches in backbone networks to SDN devices at one time. In this paper, we propose one heuristic scheme for incrementally deploy SDN switches in hybrid SDNs, the objective of which is to achieve energy saving by rerouting the flows to shut down idle links and switches as many as possible. Our solution can achieve two objectives: 1) maximizing the network control ability with a given SDN switches upgrading budget constraint, and 2) maximizing energy saving by shutting down idle links and switches with deployed SDN switches. The results of evaluations show that our scheme can achieve 95% of the number of flows controlled with only 10% of upgrading cost, and it also can achieve saving more about 10% of the total power consumption when compared to the existing solutions.
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何东标

基于网络时延的360全景视频传输算法研究
近年来,AR/VR应用,尤其是360全景视频,在学术界与工业界得到了广泛的关注。当应用360全景视频流时,网络的响应性是决定用户体验的重要因素,即视频流在传输中花费的时间将显 著影响最终用户的QoE。然而,针对360全景视频,用户每次的观察范围是相对有限的,即称之为视场(FOV),因此,发送全方位各角度的360 全景视频流显著增加了带宽使用。本文提出了一种利用网络的响应性进行视场自适应的机制,在降低带宽消耗的同时提高用户的QoE。实验结果表明,这样的机制通过选择更高的比特率,显著地改善了终端用户所看到的视频分辨率。与完整传输360全景视频流相比,使用自适应FOV机制使得分辨率提高了1.34 倍。此外,该方法提出了速率控制方法确保终端用户的QoE 根据网络条件的变化而稳定变化。这意味着,我们提出的基于网络响应性的视频分辨率和FOV自适应匹配机制,实现了增加用户QoE和充分利用网络资源这两个相互矛盾的目标。
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李峻峰

Quick NAT: High Performance NAT System on Commodity Platforms
NAT gateway is an important network system in today''''s IPv4 network when translating a private IPv4 address to a public address. However, traditional NAT system based on Linux Netfilter cannot achieve high network throughput to meet modern requirements such as data centers. To address this challenge, we improve the network performance of NAT system by three ways. First, we leverage DPDK to enable polling and zero-copy delivery, so as to reduce the cost of interrupt and packet copies. Second, we enable multiple CPU cores to process in parallel and use lock-free hash table to minimize the contention between CPU cores. Third, we use hash search instead of sequential search when looking up the NAT rule table. Evaluation shows that our Quick NAT system obtains very high scalability and line-rate throughput on commodity server, with an improvement of more than 860% compared to Linux Netfilter.
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优秀论文二等奖(1)

马腾 何东标

一种基于RDMA的云存储系统设计模式
本论文提出了一种新型的RDMA设计模式,涉及云存储系统的远程数据获取设计模式,通过该设计模式优化云数据中心的服务端,最终加速系统云存储系统,提高网络应用程序性能。
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