http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Cloud Assisted P2P Live Video Streaming over DHT Overlay Network
Pheng-Un Lim(림펑언),Chang-Yeol Choi(최창열),Hwang-Kyu Choi(최황규) 대한전기학회 2017 전기학회논문지 Vol.66 No.2
Many works have attempted to solve the scalability, the availability, and the low-latency problems of peer-to-peer (P2P) live video streaming; yet, the problems still remain. While tree-based systems are vulnerable to churn, the mesh-based systems suffer from high delay and overhead. The DHT-aided chunk-driven overlay (DCO) [1] tried to tackle these problems by using the distributed hash table (DHT), which structures into a mesh-based overlay to efficiently share the video segment. However, DCO fully depends on the capacity of the users’ device which is small and unstable, i.e., the users’ device may leave and join the network anytime, and the video server’s bandwidth can be insufficient when the number of users joining the network suddenly increases. Therefore, cloud assist is introduced to overcome those problems. Cloud assist can be used to enhance the availability, the low-latency, and the scalability of the system. In this paper, the DHT is used to maintain the location of the streaming segments in a distributed manner, and the cloud server is used to assist other peers when the bandwidth which required for sharing the video segment is insufficient. The simulation results show that by using the threshold and cloud assist, the availability and the low-latency of the video segments, and the scalability of the network are greatly improved.
Clustered Segment Index Scheme for P2P VOD Service on Virtual Mesh Overlay Network
Pheng-Un Lim(림펑언),Hwang-Kyu Choi(최황규) 대한전기학회 2016 전기학회논문지 Vol.65 No.6
Video-on-Demand(VoD) is one of the most popular media streaming which attracted many researchers’ attention. VMesh is one of the most cited works in the field of the VoD system. VMesh is proposed to solve the problem of random seeking functionality. However, a large number of the DHT(Distributed Hash Table) searches in VMesh is sill the main problem which needs to be solved. In order to reduce the number of the DHT searches, the clustered segment index(CSI) scheme is proposed. In this scheme, the video segments are divided into clusters. The segment information of the video segments, which are clustered into the same cluster, are stored in the same clustered segment index that can be searched by using the hash key. Each peer also can request the required segments by using this clustered segment index. The experiment results show that the number of the DHT searches in the proposed scheme is less than that of VMesh even in case of peers leave and join the network or peers perform the fast forward/backward operations.
Use of phytotoxic rice crop residues for weed management
Pheng, Sophea,Olofsdotter, Maria,Jahn, Gary,Adkins, Steve The Korean Society of Weed Science and The Turfgra 2010 Weed Biology and Management Vol.10 No.3
There is a general perception among Cambodian rice (Oryza sativa) farmers that, after harvesting, rice crop residues that are incorporated into the field benefit the growth of the subsequent rice crop. However, the effect of this action upon weed establishment and growth has not yet been considered. A series of pot and field trials were conducted to determine whether such action could inhibit weed establishment and/or growth. The pot studies first evaluated the response of the test plant (rice line ST-3) and three weed species, barnyardgrass (Echinochloa crus-galli), small umbrella sedge (Cyperus difformis), and water primrose (Ludwigia octovalves), to the residue of 16 rice lines and the field trials were later conducted to evaluate the response of the same test plants to the residue of seven putatively allelopathic rice lines and one non-allelopathic rice line. The residue of all the studied rice lines, depending on how long they had been incorporated into the soil, reduced the establishment and growth of all three weed species, as well as the rice crop. However, if the residue's incorporation was delayed by 2 weeks or only a proportion of the residue was incorporated, the rice crop could withstand the growth-inhibiting effect, while the inhibition of the establishment and growth of the three weed species was retained. These responses of rice and the weeds to rice crop residues might provide a basis for a weed management strategy, particularly in the resource-poor rice-production systems of Cambodia.
A Scalable and Efficient Live Video Streaming Over DHT Overlay Network
Pheng Un Lim,최창열,최황규 한국엔터프라이즈아키텍처학회 2016 정보기술아키텍처연구 Vol.13 No.4
Live video streaming becomes one of the most popular internet activities in the recent years. Along with its popularity, the problems such as scalability, availability and low-latency are still the maindrawbacks of the peer-to-peer (P2P) live video streaming. The DHT-aided chunk-driven overlay (DCO)[3] tried to overcome these problems by using the Distributed Hash Table (DHT) in live video streaming. Even the performance of DCO is better than other traditional works such as tree-based system, in termsof vulnerability to churn, and mesh-based system, in terms of high delay and message overhead, thereare some problems in DCO which need to be solved. The coordinator is easy to get overloaded by manyrequests because one coordinator is responsible for storing the chunk index of several segments. Moreover, the number of nodes that the video server is responsible for sending the video segment toare not clearly defined. To solve these problems, in this paper, a more efficient approach of using thecoordinator nodes is proposed. Furthermore, the threshold is carefully calculated in order to use theserver capacity efficiently. The server is only responsible for sending the video segment to the thresholdnodes. After that, the video segment will be shared among nodes in the network until every node receivesthe video segment. The performance evaluation results show that our work is more efficient than DCO,and the server capacity can be used efficiently if the threshold is careful defined.