Li-ming Tseng

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Papers by Li-ming Tseng

Energy Efficient Min Delay-based Geocast Routing Protocol for the Internet of Vehicles

J. Inf. Sci. Eng., 2015

Energy efficient routing protocols can potentially reduce the amount of energy consumed in packet... more Energy efficient routing protocols can potentially reduce the amount of energy consumed in packet forwarding. However, existing literature lacks studies on improving green performance of geocast routings for the Internet of Vehicles. Therefore, this study proposes an energy efficient min delay (EEMD)-based geocast routing protocol to find optimal relay nodes by incorporating energy consumption and packet delivery delay. We introduce energy efficiency in packet forwarding as a more appropriate indicator than energy consumption. We present a green protocol model and analyze its green networking performance in packet forwarding. Extensive simulation shows that our designed EEMD protocol allows efficient energy-saving data forwarding under various vehicular traffic conditions.

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An Efficient Periodic Broadcasting with Small Latency and Buffer Demand for Near Video on Demand

International Journal of Digital Multimedia Broadcasting, 2012

Broadcasting Protocols can efficiently transmit videos that simultaneously shared by clients with... more Broadcasting Protocols can efficiently transmit videos that simultaneously shared by clients with partitioning the videos into segments. Many studies focus on decreasing clients' waiting time, such as the fixed-delay pagoda broadcasting (FDPB) and the harmonic broadcasting schemes. However, limited-capability client devices such as PDAs and set-top boxes (STBs) suffer from storing a significant fraction of each video while it is being watched. How to reduce clients' buffer demands is thus an important issue. Related works include the staircase broadcasting (SB), the reverse fast broadcasting (RFB), and the hybrid broadcasting (HyB) schemes. This work improves FDPB to save client buffering space as well as waiting time. In comparison with SB, RFB, and HyB, the improved FDPB scheme can yield the smallest waiting time under the same buffer requirements.

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A Seamless Broadcasting Scheme with Live Video Support

International Journal of Digital Multimedia Broadcasting, 2012

Broadcasting schemes, such as the fast broadcasting and harmonic broadcasting schemes, significan... more Broadcasting schemes, such as the fast broadcasting and harmonic broadcasting schemes, significantly reduce the bandwidth requirement of video-on-demand services. In the real world, some history events are very hot. For example, every year in March, thousands of people connect to Internet to watch the live show of Oscar Night. Such actions easily cause the networks contested. However, the schemes mentioned previously cannot alleviate the problem because they do not support live broadcasting. In this paper, we analyze the requirements for transferring live videos. Based on the requirements, a time skewing approach is proposed to enable the broadcasting schemes to support live broadcasting. However, the improved schemes require extra bandwidth for live broadcasting once the length of live shows exceeds the default. Accordingly, we proposed a scalable binomial broadcasting scheme to transfer live videos using constant bandwidth by increasing clients’ waiting time. When the scheme finds...

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A Bipolar Traffic Density Awareness Routing Protocol for Vehicular Ad Hoc Networks

Mobile Information Systems, 2015

To support an increasing amount of various new applications in vehicular ad hoc networks (VANETs)... more To support an increasing amount of various new applications in vehicular ad hoc networks (VANETs), routing protocol design has become an important research challenge. In this paper, we propose a Bipolar Traffic Density Awareness Routing (BTDAR) protocol for vehicular ad hoc networks. The BTDAR aims at providing reliable and efficient packets delivery for dense and sparse vehicle traffic network environments. Two distinct routing protocols are designed to find an optimal packet delivery path in varied vehicular networks. In dense networks, a link-stability based routing protocol is designed to take vehicles connectivity into consideration in its path selection policy and maximize the stability of intervehicle communications. In sparse networks, a min-delay based routing protocol is proposed to select an optimal route by analyzing intermittent vehicle connectivity and minimize packets delivery latency. Intervehicles connectivity model is analyzed. The performance of BTDAR is examined ...

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Detect and Notify Abnormal SMTP Traffic and Email Spam over Aggregate Network

As all the traffic between the public Internet and the customer's desktop must be interconnec... more As all the traffic between the public Internet and the customer's desktop must be interconnected through ISP's access network, this work thus makes use of the transpor- tation traffic log gathered from backbone router to develop SMTP flooding detection system (SFDS), so that the most spam could be detected and stopped at the original fan-out network. The system has been deployed over a TANet (Taiwan Academic Net- work) backbone node for assisting network users grasping the abnormal SMTP sources with suddenly increase email requests. The result indicates that there is a high proportion of the notified spam could be detected in advance.

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A Web Redirection Service for Variant Chinese Domain Name Resolution

Third International Conference on Information Technology and Applications (ICITA'05)

Many efforts in past years have been made to lower the linguistic barriers for non-native English... more Many efforts in past years have been made to lower the linguistic barriers for non-native English speakers to access the Internet. IDNA [2] focuses on access to Internationalized Domain Names (IDN) in a range of scripts that is broader in scope than the original ASCII. However, the use of character variants that have similar appearances and/or interpretations could create confusion. A variant IDL (Internationalized Domain Label), derived from an IDL by replacing some characters with their variants, should match the original IDL. In JET Guidelines [6], it is suggested that zone administrators model this concept of equivalence as an atomic IDL package that contains the variant IDLs generated according to the Language Variant Tables (LVT). In addition to the registered IDL, some of the variant IDLs are activated and stored in the zone files and thus become resolvable. However, an issue of scalability arises when the number of the activated variant IDLs is large. In this paper, we present a mechanism to resolve the variant IDLs in an IDL package into the registered IDL. Specifically, we target Han character variants. Two Han characters are said to be variants of each other if they have the same meaning and are pronounced the same. Furthermore, Han character variants usually have similar appearances. We introduce a new resource record (RR) type, denoted as VarIdx, to associate the variant IDLs with the registered IDL. Experiment results show that a small number of VarIdx RRs are sufficient for enumerating all variant IDLs in an IDL package. We then present a redirection service that uses VarIdx RRs to redirect user requests with variant IDLs to the URLs with the corresponding registered IDLs.

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Abnormal Web usage control by proxy strategies

Internet Research, 2002

The World Wide Web (WWW) has become an extremely popular information service. Large HTTP packets ... more The World Wide Web (WWW) has become an extremely popular information service. Large HTTP packets result in network congestion. Proxy cache servers are widely deployed on the Internet to overcome this obstacle. However, the approach yields an undesirable phenomenon – a small set of users misuse proxy servers to mirror the entire contents of Web sites. This behavior wastes network resources, increases WWW servers’ loads, increases users’ waiting time, and violates copyrights. Approaches to designing a proxy server with WWW usage control and to making the proxy server effective on local area networks are proposed to prevent such abnormal WWW access and to prioritize WWW usage. Finally, a system, ProxyBreaker, is implemented to demonstrate the approaches. The implementation reveals that the proposed approaches are effective, such that the abnormal Web access does not reoccur.

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Adjustable Interleaving Staircase-Harmonic Broadcasting Scheme for Highly-Demanded Videos

With the growth of broadband networks, Video-on-Demand (VoD) has become realistic. Many significa... more With the growth of broadband networks, Video-on-Demand (VoD) has become realistic. Many significant broadcasting schemes have been proposed to reduce the viewers' waiting time. However, clients are required to receive video segments altogether from all channels. This disregard not only needs a lot of client bandwidth, but also incurs more buffer requirements. To escape from these constraints, this work proposes the adjustable interleaving staircase-harmonic broadcasting scheme (AISHB), which offers a tradeoff between any two of three resources: server bandwidth, client buffer spaces, and client bandwidth. When client bandwidth is not limited, the scheme requires a client to buffer only 25% of a playing video and the waiting time is slightly higher than the optimal waiting time. In comparison with the fast broadcasting, recursive frequency-splitting, and harmonic broadcasting, AISHB saves the buffer requirements by 50%, 33%, and 33%. If client bandwidth is restricted, AISHB achi...

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Enhanced harmonic data broadcasting and receiving scheme for popular video service

IEEE Transactions on Consumer Electronics, 1998

For a popular movie, in order to minimize the service delay with a given bandwidth, currently the... more For a popular movie, in order to minimize the service delay with a given bandwidth, currently the harmonic broadcasting scheme can provide users with the shortest waiting time to approach near video-on-demand service. This paper presents an enhanced scheme, which can improve the bandwidth utilization and reduce further the viewers' waiting time.

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Harmonic broadcasting for video-on-demand service

IEEE Transactions on Broadcasting, 1997

Using coiiventional broadcasting, if we want to support a 120-ininute popular movie every 10 minu... more Using coiiventional broadcasting, if we want to support a 120-ininute popular movie every 10 minutes, we need 12 video channels. Suppose the set-top box at client end can buffer portions of the playing video on disk. Pyramid broadcasting schemes can reduce the bandwidth requirements to 5.7 channels. We present a new scheme which only needs 3.2 channels. For a movie with length D minutes, if we want to reduce the viewer waiting time to D/N minutes, we only need to allocate H(N) video chaiinels to broadcast the movie periodically. Where H(N) is the harmonic number of N, H(N)=I+1/2+ ... +I/N. In order to support video-ondemand service for a popular movie, the new scheme greatly reduce the bandwidth requirements.

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Content Delivery Network with Hot-Video Broadcasting and Peer-to-Peer Approach

Journal of information science …, 2004

With the growth of bandwidth, video/audio streaming services have become popular, and are conside... more

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Improving Internet archive service through proxy cache

Internet Research, 2003

Traditionally, file transfer protocol (FTP) servers are major archive providers and users apply t... more Traditionally, file transfer protocol (FTP) servers are major archive providers and users apply the Archie server to locate FTP archives. With the extreme popularity of the WWW, Web servers are now important archive providers and users download archives via HTTP. To reduce HTTP traffic, proxy cache servers are deployed on the Internet. However, we find the hit rate of archives in cache servers is quite low. This study proposes a combination of caching and better searching mechanisms to alleviate the problem. We enable a proxy server to automatically collect WWW and FTP archives from its cache, organize them in the form of an FTP directory, and then offer the directory list to the Archie. Accordingly, users can find archives on WWW and FTP servers through the Archie, and they can directly download archives from the proxy server, thus improving the reuse of cached archives. A system was implemented and operated in a real environment to evaluate the approach and results are discussed.

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Variant Chinese Domain Name Resolution

ACM Transactions on Asian Language Information Processing, 2008

Many efforts in past years have been made to lower the linguistic barriers for non-native English... more Many efforts in past years have been made to lower the linguistic barriers for non-native English speakers to access the Internet. Internet standard RFC 3490, referred to as IDNA (Internationalizing Domain Names in Applications), focuses on access to IDNs (Internationalized Domain Names) in a range of scripts that is broader in scope than the original ASCII. However, the use of character variants that have similar appearances and/or interpretations could create confusion. A variant IDL (Internationalized Domain Label), derived from an IDL by replacing some characters with their variants, should match the original IDL; and thus a variant IDN does. In RFC 3743, referred to as JET (Joint Engineering Team) Guidelines, it is suggested that zone administrators model this concept of equivalence as an atomic IDL package. When an IDL is registered, an IDL package is created that contains its variant IDLs generated according to the zone-specific Language Variant Tables (LVTs). In addition to ...

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An efficient staircase-harmonic scheme for broadcasting popular videos

Second IEEE Consumer Communications and Networking Conference, 2005. CCNC. 2005, 2005

With the growth of broadband networks, Video-on-Demand (VoD) has become realistic. Many significa... more With the growth of broadband networks, Video-on-Demand (VoD) has become realistic. Many significant broadcasting schemes have been proposed to reduce the viewers' waiting time. However, clients are required to receive video segments altogether from all channels. This disregard incurs more buffer requirements. To escape from this constraint, we propose a novel interleaving staircase-harmonic broadcasting (ISHB) scheme, which focuses on buffer saving, and the viewers' waiting time approaches to theoretical lower bound. Furthermore, the scheme uses the interleaving technology to mitigate the effect of packet losses. Given a fixed bandwidth, the ISHB scheme buffers only 25% of a playing video. In comparison with the fast broadcasting (FB), recursive frequency-splitting (RFS) and interleaving harmonic broadcasting (IHB) schemes, the ISHB scheme saves the buffer requirements by 50%, 33% and 33%.

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Fast and lossless broadcasting schemes for VBR-encoded hot videos

Proceedings. 2004 12th IEEE International Conference on Networks (ICON 2004) (IEEE Cat. No.04EX955), 2004

... 241 7, pp. 66-77, San Jose, Califomia, 1995. Hsiang-Fu Yu, Hung-Chang Yang, Yi-Ming Chen, Li-... more

A scheduling system for exploiting data and task parallelism on PC laboratory clusters

Campus-Wide Information Systems, 2003

ABSTRACT Presents a framework for deciding on a good execution strategy for a given program based... more ABSTRACT Presents a framework for deciding on a good execution strategy for a given program based on the available data and task parallelism in the program on PC laboratory clusters. Proposes a virtual cluster scheduling scheme to take account of the relationships between tasks for task parallelism, and also processor speed, processor load and network environment to balance load for data parallelism in a PC cluster environment. The approach is very effective in terms of the overall execution time, and demonstrates the feasibility of automatic cluster assignment, processor set selection and data partition functions for data and task parallel programs.

On Optimal Broadcasting Scheme for Popular Video Service

… , IEEE Transactions on, 2002

I n order to approach video-on-demand (VOD) service, we can allocate more bandwidth to broadcast ... more I n order to approach video-on-demand (VOD) service, we can allocate more bandwidth to broadcast a popular video more frequently to reduce viewers' waiting time. Using broadcasting scheme to support a popular video periodically, in order to guarantee a given waiting time, the harmonic broadcasting scheme needs the least bandwidth in the existing schemes. I n this paper, we will show that using any broadcasting scheme, the minimum bandwidth requirement for the same waiting time is the same as the harmonic broadcasting scheme. Therefore, for a popular video, in order to approach near VOD service, the harmonic broadcasting scheme is an optimal broadcasting scheme that needs the least bandwidth for a given viewers' waiting time.

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IDN server proxy architecture for Internationalized Domain Name resolution and experiences with providing Web services

ACM Transactions on Internet Technology, 2006

The composition of traditional domain names are restricted to ASCII letters, digits, and hyphens ... more The composition of traditional domain names are restricted to ASCII letters, digits, and hyphens (abbreviated as LDH). This makes it difficult for many to use their native language to name and access their Internet hosts. The IETF IDN (Internationalized Domain Name) Working Group proposes a mechanism, IDNA (Internationalizing Domain Names in Applications), for internationalized access to multilingual domain names. The proposal uses a preparation process that converts a Unicode IDN into an ACE (ASCII Compatible Encoding) string that uses only LDH. Thus, applications can look up the ACE string by using the existing DNS infrastructure. However, some of the domain name strings embedded in multilingual content do not have any charset tag so they cannot appropriately be converted into ACE strings. We noticed that many Internet applications allow users to use non-ASCII domain names. We were motivated to design an architecture for IDN resolution as well as to minimize the cost of modifying legacy Internet applications. We specifically focus on designing an IDN server proxy, which is located on the domain name server side, to handle domain names in multiple encodings. In this article, we study several architecture design issues including detection of charset encoding, routing of non-ACE IDN lookup requests, and so on.

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A Smooth Recursive Frequency-Splitting Scheme for Broadcasting VBR-Encoded Hot Videos

Lecture Notes in Computer Science, 2004

ABSTRACT One way to broadcast a popular video is to partition the video into segments, which are ... more ABSTRACT One way to broadcast a popular video is to partition the video into segments, which are broadcasted on several streams periodically. The approach lets multiple users share streams; thus, the stress on the scarce bandwidth can be alleviated without sacrificing viewers’ waiting time. The segment partition can be categorized into two types: vertical and horizontal. One representative scheme based on vertical segmentation is the recursive frequency-splitting (RFS) broadcasting, which has the smallest waiting time in the literature. Based on the scheme, we propose a smooth RFS (SRFS) scheme, which can broadcast VBR-encoded videos smoothly. By dynamically arranging portions of the segments on the streams, the approach reduces the peak bandwidth consumption and the variance. Finally, we conducted a simulation to evaluate our scheme. The results indicate that the SRFS outperforms the RFS scheme on reducing the bandwidth variance and peak. The reductions can even reach 96% and 12%. The overhead is slightly higher average bandwidth.

Fast broadcasting for hot video access

Proceedings Fourth International Workshop on Real-Time Computing Systems and Applications, 1997

Abstract Using multiple channels to broadcast a popular video can reduce the viewer's waitin... more

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