Private:progress-almowuena

Summer 2011

• Courses:
  • CMPT 899: Ph.D. Thesis

• June 15 to July 17:
  • A simple algorithm for the hybrid multimedia streaming problem is proposed [Here]. At this moment, I am trying to study and simulate two scenarios based on the proposed scheme: 1) the multimedia file is sent and multicasted with high data rate in a short period of time (i.e. send a burst of data), which logically reduce the energy consumption; and 2) the desired content is streamed with low data rate, which enhances the possibility of late clients to join the multicasting session and then reduces the amount of unicast streams in the system. In my point of view, finding the optimal trade-off between both two scenarios can be an interesting objective.

• June 3 to July 14:
  • Since Dr. Cheng-Hsin Hsu pointed out that both problem statement as well as our proposed algorithm needs additional clarification, we agreed on limiting the problem statement to be more specific as follows: in a mobile network whose clients possess battery-powered devices with low computational resources, find an energy-efficient multimedia streaming scheme with an objective of maximizing the number of concurrent users. The proposed algorithm should handle an asynchronous request by either initiating a unicast streaming or extending an existing multicasting session. Assuming a desired multimedia content is properly delivered to the target base station without encountering any bottlenecks, the service delay required must be lower than a predefined threshold. Given a buffer size of B kb, the proposed scheme should ensure the absence of any buffer violation in the entire system. A buffer violation occurs when a receiver has no space to store the data received during a burst transmission (buffer overflow).
  • I extended the related work section by including six additional resources. Currently, both introduction and related work sections are completed, so they can be accessed Here.
  • Meanwhile, I am also aiming on doing some simulation, so I am still trying to implement the three algorithms presented in Here. I chose this paper because it seems a good candidate to be compared with our proposed scheme.

• June 13 to July 2:
  • I prepared a brief review about four streaming algorithms which seems very close to our proposed method Here. Clearly, most researchers had not considered the energy consumption in their works, so an important contribution of our proposed scheme is taking this point into account.
  • Since mobile networks share many common aspects with wireless sensor and ad hoc networks, I also investigated the current solutions proposed for the multicast-unicast problem in these two configurations Here. Since these techniques take advantages of multipath routing and neighbouring buffers, these approaches cannot be useful for the cellular network due to the absence of intermediate nodes in its infrastructure.
  • Four main questions can be asked in the hybrid multimedia streaming problem: 1) How can we multicast or unicast a required multimedia file? 2) What is the cost of changing the mode from unicast to multicast and vice versa? 3) How can we schedule a number of simultaneous requests belonging to different streaming contents? and 4) What is the impact of handover on the performance of the proposed algorithm? Next week, I will try to answer the first two questions.

• May 21 to June 12:
  • A simple algorithm for the hybrid multimedia streaming problem is proposed. In this algorithm, a base station usually responds for an incoming request by unicasting the desired video directly to the mobile client. Nevertheless, it can also decide to start a multicasting session for a number of simultaneous users. Such decision is basically based on a combination of two parameters: the length of the required video file as well as its popularity in the current geographical location.
  • This algorithm should be evaluated using four metrics: the playback delay, the bandwidth usage, the power consumption, and the buffer requirements for both base station and mobile clients. Therefore, I am still working on obtaining the mathematical formulas for these four metrics taking into account the frequent occurrence of handover. In my opinion, considering this point will distinguish our algorithm from any other method proposed for wireless networks.

• May 7 to May 20:
  • In the report written by Som, many equations were given based on the assumption that video signals have a fixed date rate. Unfortunately, this is not always the case. For instance, video files generated using MPEG compression schemes are utilizing variable bit rates. Therefore, I am working on reformulating the equations for both bandwidth requirements and power consumption in order to take the variable bit rates into consideration.
  • In the same report, the video length was taken into account in order to determine the selection between unicasting and multicasting. Besides that, I am trying to consider the popularity of the wanted video. In a simple manner, requests for popular videos will be combined together to initiate a multicasting stream, whereas requests for videos with low-demand will be unicasted to their audiences. Determining the popularity of a particular video is typically an easy process since many websites include such information in the video details. However, we can make the base stations in mobile networks monitor the activities of their local users. Enabling this feature will eventually increase the overall performance of the system because the requests of certain videos are usually affected by the geographical regions. For example, people sitting near a hockey stadium are more likely to be interested in sport video than those who are sitting by the ocean or a natural park.
  • I am also working on another idea relying on the popularity concept. People often are looking to watch certain clips from a popular video. In other words, a long interview whose length is more than 60 minutes usually features several topics. In most cases, users are not interested in watching the entire interview; they are looking for specific parts of the interview. If you determine the popular parts, it would be easy to optimally divide the entire video into a number of segments, leading to obtain an efficient multicasting scheme. Even though this idea seems a little bit complex, it will be worthwhile to investigate more in order to propose efficient hybrid streaming algorithm.
  • Although researchers are usually focusing on a true video-on-demand, it can be acceptable for many free video-on-demand services to add short advertisement clips, especially when these ads are highly related to the required videos. If we stream advertisement clips with different lengths, we can combine all incoming request and then initiate a new multicasting steam. To illustrate, the fist requests will be given an ad with an acceptable length and the second requests will be given shorter ads, and so on. Ensuring all these advertisement clips are finishing at the same time, starting a new multicasting stream will be possible. I am trying to avoid applying this idea in our proposed algorithm, but it can be an option if we try to earn some time before initiating a new multicasting stream.

• Apr 25 to May 6:
  • Refocusing on the multicast-unicast multimedia streaming problem in mobile networks.
  • Trying to understand the simulator implemented by Somsubhra Sharangi.

Spring 2011

• Courses:
  • CMPT 705: Design and Analysis of Algorithms
  • CMPT 820: Multimedia Systems

• Apr 01 to Apr 22:
  • Focusing on my coursework; finalizing some assignments and projects as well as preparing for a final exam.

• Feb 07 to Feb 21:
  • Reviewing the current solutions proposed for the multicast-unicast multimedia streaming problem in wireless sensor and ad hoc networks, and writing a brief report about this issue.
  • Reading about the multimedia broadcast and multicast services in 3G mobile networks and their standards.

• Jan 31 to Feb 06:
  • Understanding the concept of three important methods in the field of internet multimedia streaming: Batching, Patching, and Periodic Broadcasting.
  • Analyzing the problem of hybrid multimedia streaming over wireless networks.
  • Exploring different techniques for hybrid multimedia streaming in wireless and ad hoc networks.

• Jan 24 to Jan 30:
  • Preparing for a midterm in addition to completing two assignments related to my coursework.
  • Surveying the main methods in the field of content based 3D shape retrieval.

• Jan 17 to Jan 23:
  • Trying to comprehend the basic digital video coding standards, including JPEG and MPEG.
  • Reading brief introduction about 3D technology, focusing on its current coding algorithms.
  • Exploring the main security concerns in cloud computing, particularly the concept of homomorphic encryption.