
Mabo Robert ItoUniversity of British Columbia | UBC
Mabo Robert Ito
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Publications (143)
While energy efficiency is essential to extend the battery life of embedded devices, performance cannot be ignored. High performance superscalar embedded processors are more energy efficient than low performance scalar processors, however, they consume more power which is very limited in battery operated deeply embedded industrial devices. In this...
While energy efficiency is essential to extend the battery life of embedded devices, performance cannot be ignored. High performance superscalar embedded processors are more energy efficient than low performance scalar processors, however, they consume more power which is very limited in battery operated or self powered embedded industrial devices....
Low cost and low power scalar embedded processors can issue only a single instruction per cycle which results in longer execution time for applications and consequently lower energy efficiency. Superscalar processor that can issue multiple instructions per cycle are more energy efficient than scalar processors, however, they consume more power whic...
Smart embedded devices most often operate on batteries and in some cases these batteries cannot be replaced so frequently. As a result, both the available power and energy budgets are severely limited which forces designers to use low performance processors that use the least amount of power possible. The conundrum is that an increasing number of s...
Streaming video over IP networks has become increasingly popular; however, compared to traditional data traffic, video streaming places different demands on Quality of Service (QoS) in a network, particularly in terms of delay, delay variation, and data loss. In response to the QoS demands of video applications, network techniques have been propose...
Guaranteed services in the computer network often require a single reserved path, which easily suffers from single link failures. This paper introduces a backup path computation algorithm, TP, which is intended to compute unreserved backup paths to overcome a single link failure in the network. Simulations are performed to compare TP to other known...
This paper presents an experimental evaluation on the feasibility of using an adaptive clock to enhance the performance of a Fast Fourier Transform (FFT). The FFT is implemented on an FPGA and results are simulated using commercial EDA tools. Dynamic power consumption and processing speed are compared to a standard FFT implementation using a fixed...
One of the challenges of large-scale network simulations is the lack of scalable and realistic Internet topology generators. Previous topology generators are either not scalable to millions of nodes, or not able to capture characteristics of the Internet topology. In this work, we propose a topology generator which can generate accurate large-scale...
In this paper we propose a new technique for modeling three-dimensional rigid objects by encoding the fluctuation of the surface
and the variation of its normal around an oriented surface point, as the surface expands. The surface of the object is encoded
into three vectors as the surface signature on each point, and then the collection of signatur...
Providing high quality-of-service using a single reserved path easily suffers from single link failures. This paper provides a scalable solution, TPmax-R, to tolerate single link failures. TPmax-R is based on an existing method, AvoidPBO-R. TPmax-R reduces the communication cost incurred by AvoidPBO-R to a scalable level. Instead of broadcasting ro...
Guaranteed, high-quality service in the computer network often requires a single reserved path. However, a single path can easily suffer from single point failures. This paper provides a solution to handle flows when their reserved primary paths fail. The solution pairs a reserved primary path with an unreserved backup path. When a failure occurs a...
Guaranteed, high-quality service in a computer network often requires a single reserved path. Such a path can easily suffer from single point failures. Thus, to continuously provide the same high-quality service guarantee both before and after a link failure, each flow requires both a reserved primary path and a backup path. One solution category i...
Loss control is an essential issue for video transportation over IP networks. Buffer management is a traditional network technique to protecting video data against IP packet loss. In this paper, a new innovative use of packet scheduling to meet the loss constraints of video communication is proposed. A packet-scheduling scheme at a router that assu...
Traffic that requires high service quality often uses a single path with reserved resources for data transmission. The use of a single dedicated path suffers from single link failures. This paper provides a solution (TPmax-S) that uses scalable routing information to find alternate paths in the event of a single link failure in the network. When su...
Traffic that requires high service quality often uses a single path with reserved resources for data transmission. The use of a single dedicated path suffers from single link failures. This paper provides a solution (TPmax-S) that uses scalable routing information to find alternate paths in the event of a single link failure in the network. When su...
The current routing algorithms of DHT-based P2P systems have a large end-to-end delay and inconsistent routing performance because of their random selection of identifiers (IDs). In this paper, an Internet topology based overlay construction method is proposed for tree-based DHTs. The node ID is divided into three parts and assigned according to th...
Simulation of P2P systems at the scale of millions of nodes is important because some problems with the protocols or their implementations might not appear at smaller scales. In this work, we propose a parallel message-level simulator, P2PNet, which can simulate P2P systems with up to millions of nodes. P2PNet applies the technique of time expansio...
Streaming video over IP networks has become increasingly popular; however, compared to traditional data traffic, video streaming places different demands on quality of service (QoS) in a network, particularly in terms of delay, delay variation, and data loss. In response to the QoS demands of video applications, network techniques have been propose...
This paper proposes a new technique for modeling and matching three-dimensional rigid objects by encoding the fluctuation of the surface and the variation of its normal around an oriented point on the surface as the surface expands. The surface of the object is encoded into two two-dimensional curves as the surface signature on each point, and then...
VoIP applications have grown rapidly and continue to enjoy exponential growth due to largely reduced cost and wider range of advanced services, as compared to traditional telephone network., however, they face many technical challenges. One of major challenges is the provision of quality of service. Presently, VoIP quality is not as good as achieve...
Traditional network-level Quality of Service (QoS) techniques are efficient from a network perspective, but they have not provided end-to-end QoS that is satisfactory to users. In this letter, a Coordinated Packet Discard scheme for the distribution of end-to-end QoS requirements into local loss constraints, as well as provision of local loss assur...
Current network techniques provide quality of service (QoS) from the viewpoint of the network. However, these schemes often do not result in satisfactory performance for application users. The paper proposes two new proactive resource allocation schemes for satisfying the perceived QoS requirements of video users. The schemes are proactive in the s...
Shortest path first (SPF) routing protocols, such as OSPF and IS-IS are currently the dominant intra-domain IP routing protocols and are widely used in the ISP backbones. Although the traffic on the Internet is highly dynamic, OSPF and IS-IS are not adaptive to the changing traffic, because the shortest path generated by these protocols are based o...
A dynamic weight mapping adaptive routing algorithm (DWMAR) is proposed in this paper to provide an optimized and stable adaptive routing protocol. The online dynamic weight mapping function is customized for each link. DWMAR adopts different adaptive policies on different link loads to make up for the unstable nature of adaptive routing. The perfo...
An important issue for video transmission over IP networks is the preservation of perceived video quality despite packet loss. Packet loss can be detrimental to compressed video. However, reducing packet loss to a very low level is difficult with current techniques. Furthermore, even a very low objective loss probability can still seriously distort...
This paper proposes an intelligent scheme to enhance Quality of Service for video streaming over IP networks. The idea is to discard packets intelligently at a router in Active Networks (AN) before the buffer is full. This paper also presents an AN-based network node architecture to support the proposed scheme. Our simulation results show that it i...
An important issue for video transmission over IP networks is preservation of perceived video quality despite packet loss. Packet loss can be detrimental to compressed video. However, reducing packet loss to a very low level is difficult with current loss control techniques. Furthermore, even a very low objective loss probability can still seriousl...
Packet loss due to network congestion causes degradation in the quality of networked video transmitted over IP networks. Buffer management and packet scheduling are two key router-based quality of service (QoS) control techniques. Existing buffer management mechanisms mainly focus on preventing network congestion in order to reduce packet loss. How...
Buffer management plays an important role for enhancing quality of service (QoS) for video streaming over IP networks. However, most existing buffer management techniques have been developed according to the network's point of view; consequently, QoS requirements from users' perspectives are not well satisfied. The paper proposes a novel buffer man...
Various levels of Quality of Service (QoS) can be provided within a network by using integrated services, differentiated services, and active networking approaches. While these three approaches have been presented in several articles, comparison among them is lacking. Therefore, this article examines these three approaches for both their key functi...
Traditional buffer management techniques, which are based on reducing packet loss, fail to ensure user expected video quality. In www3.informatic.uni-wuerzburg.de, we proposed an alternative buffer management approach, called FDDT, which focuses on controlling packet loss distribution. Experiments have shown that FDDT significantly improves both vi...
This paper proposed a receiver-driven layered multicast scheme using active networks (RLM-AN). The multicast tree is regarded as a set of virtual links. TCP-friendly congestion control and FEC-based error control are performed on each virtual link. In order to solve the loss path multiplicity problem, the intermediate active nodes also perform erro...
Video streaming over IP networks requires end-to-end loss guarantees. In order to achieve the required end-to-end loss performance, new algorithms for the distribution of end-to-end loss requirements into local loss constraints, as wells as provision of local loss assurance, are proposed. Much of recent research pays little attention to the problem...
Video streaming over IP networks requires end-to-end loss guarantees. In order to achieve the required end-to-end loss performance, new algorithms for the distribution of end-to-end loss requirements into local loss constraints, as well as provision of local loss assurance, are proposed. Much of recent research pays little attention to the problem...
Packet scheduling is typically designed to support the delay requirements of video communication. In this paper, a new innovative use of packet scheduling to provide loss guarantees is proposed. A packet scheduling scheme at a router that assures that intra and interstream loss requests for video transportation are met was developed and evaluated u...
Packet loss due to network congestion causes degradation in the quality of networked video transmitted over IP networks. Previous buffer management methods have been designed to prevent network congestion in order to reduce packet loss. However, a low packet loss ratio by itself does not necessarily translate to high video quality, so these methods...
In true VOD systems, the power to access and read the data storage devices, the processing power in the servers and the bandwidth consumption on the network impose an upper bound on the number of parallel sessions supported by the server. To improve access to VOD services, we propose in this paper a technique that consists of exposing the contents...
The paper introduces a new scheme of receiver-driven layered multicast using active networks (RLM-AN). As most layered multicast schemes conduct an end-to-end congestion control mechanism, we propose a distributed TCP-friendly congestion control scheme. The multicast tree is regarded as a set of virtual links and TCP-friendly congestion control is...
Packet scheduling is typically designed to support the delay requirements of video communications. In this study, a new innovative use of packet scheduling to provide loss guarantees is proposed. A packet scheduling scheme at a router that assures that intra and inter-stream loss requests for video transportation are met, and it was developed and e...
An important issue for video transmission over IP networks is preservation of perceived video quality despite packet loss. Packet loss can be detrimental to compressed video. However, reducing packet loss to a very low level is difficult with current loss control techniques. Furthermore, even a very low objective loss probability can still seriousl...
Quality of service (QoS) guarantees can be provided within a network by relying on the integrated services, differentiated services, and active networking approaches. The three approaches are presented in several papers, but none provide a comparison between all of them. Therefore, this paper overviews the key functionality and the relative strengt...
Requirements specification notations are developed by organizations in order to meet their specific needs. For example, the Threads-Capabilities notation, an in house notation at Raytheon Systems Canada, Ltd., has been developed and used for specifying their complex, large scale, air traffic control systems. It is a semi-formal, structured, natural...
In this paper, we present two mechanisms that reduce indirect mispredictions of two-stage branch predictors: First, to reduce conflict misses in the first stage predictor, a new cache scheme is proposed instead of a branch target buffer (BTB). Second, to reduce mispredictions caused by the second stage predictor, efficient predict and update rules...
In this paper, we present a new hybrid branch predictor called the GoStay2, which can effectively reduce indirect misprediction
rates. The GoStay2 has two different mechanisms compared to other 2-stage hybrid predictors that use a Branch Target Buffer
(BTB) as the first stage predictor: Firstly, to reduce conflict misses in the first stage, a new e...
We present an efficient cache scheme, which can considerably
reduce instruction cache misses caused by procedure call/returns. This
scheme employs N-way banks and XOR mapping functions. The main function
of this scheme is to place a group of instructions separated by a call
instruction into a bank according to the initial and final bank
selection m...
Adaptive Viewers' Bias Based (AVBB) caching algorithm considers recency and frequency of past requests along with the video characteristics as solid criteria for replacing an object. Each cached video has a cumulative priority function which is a basically a sum of individual priority functions of the past requests. The parameters of the priority f...
A pipelined algorithm and parallel architecture is under
development for real time detection of landmines. Our previous work has
dealt with monochromatic images from airborne active infrared scanners
and images from a low-altitude aircraft-mounted multi-spectral scanner.
Because of the nature of the sensors and the aerial observation
platform, the...
A user-friendly reconfigurable and modular monitoring and control
system for computerized numerical control (CNC) machine tool control and
machining process monitoring is described. The main part of the system
is a fully integrated combination of a real-time preemptive operating
system (ORTS-DSP) for machine-level soft real-time tasks running on
di...
A distributed VOD system includes several VOD sub-systems, each
VOD sub-system consisting of an archive server (AS), a continuous media
server (CMS) and a medata DB. A VOD sub-system employs an object
replacement algorithm by which a video is selected to be replaced by a
new video. Upon a miss, the VOD system must decide onto which CMS to
load the...
This paper presents a new instruction cache scheme: the TAC (Thrashing-Avoidance Cache). A 2-way TAC scheme employs 2-way banks and XOR mapping functions. The main function of the TAC is to place a group of instructions separated by a call instruction into a bank according to the Bank Selection Logic (BSL) and Bank-originated Pseudo-LRU replacement...
In order to transfer a new tool or technique to industry, project managers need some kind of an evaluation to determine if its benefits outweigh the costs. There are several ways to evaluate a new tool or technique including cases studies, pilot projects, or experiments. In this work, an experimental evaluation is selected to objectively evaluate a...
The effects of packet network error and loss on MPEG-2 video streams are very different from those in either wireless bitstreams
or cell-based networks (ATM). We report a study transporting high-quality MPEG-2 video over an IP network. Our principal objective
is to investigate the effects of network impairments at the IP layer, in particular packet...
This paper presents a novel recursive algorithm for generating
higher order m-dimensional (m-D) convolution by combining the
computation of 3<sup>m</sup> identical lower order (smaller size)
convolution computations, and its implementation in parallel VLSI
networks. The resulting VLSI architectures have very simple modular
structure, highly regular...
This correspondence presents a new recursive formulation of Toom's
algorithm that allows the generation of higher order (longer size)
one-dimensional (1-D) convolution architectures from three lower order
(shorter sizes) convolution architectures. Our methodology is based on
manipulating tensor product forms so that they can be mapped directly
into...
An abstract is not available.
This is a survey of the state of the art in delivering IP services over ATM networks, as it stands in the second quarter of 1997. It also includes a look at the alternatives to that set of technologies. The technology and the choices are changing "on the fly", and have evolved significantly during the course of this project. Moreover, the issues ar...
The architecture of the Berkeley distributed hierarchical video-on-demand (VOD) system consists of continuous media servers basically standing as a cache between the archive servers and the clients. In this paper, we first describe the features of a new cache management algorithm called AVBB (Adaptive Viewers, Bias-Based). With the firm belief that...
The architecture of a hierarchical video-on-demand (VOD) system
consists of continuous media servers (CMS) which basically stand as a
cache between the archive servers (AS) and the clients. The adaptive
viewers' bias-based (AVBB) cache management algorithm is
higher-performing than any existing ones because it considers and adapts
to the video char...
The architecture of the Berkeley distributed hierarchical
video-on-demand (VOD) system consists of continuous media servers (CMS)
basically standing as a cache between the archive servers (AS) and the
clients. Many replacement policies used in cache management, we notice,
is restricted in that they consider only one (or few) parameters to
decide wh...
This paper presents the advantages of using a Stimulus Response Requirement Specification (SRRS) technique to reduce costs, development time, and errors in the generation of system level test cases in comparison to using a Structured Analysis (SA) technique. A SRRS technique describes requirements in terms of externally visible inputs (stimuli), pr...
This paper develops an efficient buffer management scheme that
makes generic ATM switches capable of supporting delay-sensitive as well
as loss-sensitive traffic. The proposed scheme aims at enhancing the
performance of ATM switches by maintaining the head cells of output
queues in relatively short dedicated output buffers, while maintaining
the lo...
Some of the main issues in development and use of a tool for simulation and analysis of hybrid systems are discussed. This tool called GPNSAT (global Petri net simulation and analysis tool) was developed to assist in our research into hybrid systems. GPNSAT simulates simple, timed and and global Petri nets. The analysis of nets is performed by both...
In this paper, a new methodology for modeling and simulation of hybrid manufacturing systems is presented. This methodology which is based on an extension of Petri nets can be used to model, simulate and analyze systems with both time and event-driven parts. This new extension is called GPN (global Petri net). Here we show how it is used to model a...
A pipe-lined algorithm and parallel architecture is under development for real time detection of sparse small objects in images. Monochromatic images from an airborne active infrared scanner, images from a low-altitude aircraft-mounted multispectral scanner, and passive infrared imagery obtained from cameras mounted on ground vehicle are the image...
This is a survey of the state of the art in delivering IP services over ATM networks, as it stands in the second quarter of 1997. It also includes a look at the alternatives to that set of technologies. The technology and the choices are changing "on the fly", and have evolved significantly during the course of this project. Moreover, the issues ar...
An open, reconfigurable and modular process monitoring and CNC operating system has been developed. The process monitoring system runs on a dedicated DSP board with analog input and output channels. New process control and signal processing algorithms can be rapidly applied by sequential execution of script commands provided in a library. The CNC o...
An hierarchical motion-control design strategy is presented to integrate various intelligent machining modules to CNC systems. There are two independent buses in the CNC system. Modular and independent processor boards reside in the primary bus which is global for manufacturing process monitoring, control and machine tool position commands. A digit...
This paper presents an efficient methodology for decomposing and modularizing large computations so that they can be easily mapped onto FPGAs and other programmable logic structures. The paper focuses on the multidimensional discrete cosine transform (DCT). The main advantage of the proposed decomposition strategy is that it enables constructing la...
This paper presents an efficient methodology for decomposing and modularizing large computations so that they can be easily mapped onto FPGAs and other programmable logic structures. The paper focuses on the multidimensional discrete cosine transform (DCT). The main advantage of the proposed decomposition strategy is that it enables constructing la...
Synthetic aperture radar (SAR) signal processing poses a
significant challenge due to its very large computation and data storage
requirements. The paper compares various design approaches for parallel
SAR processors capable of processing high resolution satellite SAR data
at a rate of 1/10 real-time. Sample designs are presented for parallel
proce...
The field of distributed multimedia systems (DMS) has received a great deal of attention. Multimedia synchronization specification is an important issue in DMS since it must be addressed in the first phase of the development lifecycle. This paper presents a classification of multimedia application requirements and a comprehensive comparison of vari...
Image formation from squint mode synthetic aperture radar (SAR) is limited by image degradations caused by neglecting the range-variant filtering required by secondary range compression (SRC). Introduced here is a nonlinear FM chirp scaling, an extension of the chirp scaling algorithm, as an efficient and accurate approach to range variant SRC. Two...
Synthetic aperture radar (SAR) signal processing poses a significant challenge due to its very large computation and data storage requirements. This paper presents the computational requirements of a typical high resolution satellite SAR data processing scenario. A classification of approaches to partitioning the SAR problem for parallel processing...
The purpose of this study was to detect and count feed pellets in a sea cage using underwater video cameras. Using a light-compensating camera pointing straight down in the water column, extruded pellets appear white. This effect made it possible to detect and count feed pellets during a feeding event. The manual counting of food pellets from video...
In this paper we present a new methodology for modeling and
analysis of faults in hybrid systems. This new methodology is targeted
for use in real-time control systems. We describe a new tool which can
be used to model both the plant and the computer controlling it. The
modeling is performed by an extension of Petri nets called the global
Petri net...
In the traditional object-oriented languages, the object stands for basic entity with attributes (representing data structures) and methods (services that can be provided by the object). Nevertheless an important part of the object that concerns its behavior is still to be defined precisely. The behavior can he defined as rules for the use of metho...
This paper presents novel VLSI interconnection schemes that can be
used to “modularize” parallel convolution circuits. Our
methodology implements Toom's algorithm and is based on tensor product
factorization of linear convolution into three cascaded stages. The
resulting networks have very simple modular structure and highly regular
topology. Addit...
A distributed multimedia example is specified in natural language,
OCPN, XOCPN, TSPN, path operators, and LOTOS. The XOCPN and TSPN
specifications are reworked using standard Petri net modelling
techniques to reduce the complexity by factors of 20 and 9 respectively.
The specifications are discussed in terms of their complexity and
ability to model...
We present a multimedia architecture and a data retrieval model for supporting simultaneously multiple clients requesting files of different play-back rates. We study its performance using a circular SCAN disk scheduling policy in terms of the maximum number of concurrent video streams it can support. We present new techniques, namely, the maximum...
This paper presents highly parallel VLSI structures for linear
convolution. Our methodology implements Toom's algorithm and is based on
mapping a modified version of the tensor product factorization proposed
by Granata et al. (1991). The resulting networks have very simple
structure, highly regular topology, and use simple bit-serial devices.
Addit...
An algorithm for real-time minefield detection from monochromatic airborne imagery must analyze the shape and spatial inter-relationship between compact, several pixel wide, regions that contrast with background. The regions are sparsely distributed over large areas and input data rates are very high. A hierarchical algorithm is described which mee...
Synchronization constitutes an important research field in multimedia communication. The synchronization problem has been addressed in the literature in two distinct levels: specification and design. On the specification level, several formal models have been proposed, which are mostly variations of the Petri net model. Although some models are dee...
Welcome to the fourth IFIP workshop on protocols for high speed networks in Vancouver. This workshop follows three very successful workshops held in Ziirich (1989), Palo Alto (1990) and Stockholm (1993) respectively. We received a large number of papers in response to our call for contributions. This year, forty papers were received of which sixtee...
Petri nets have proven themselves to be an excellent modeling and
analysis tool for discrete event or asynchronous systems. On the other
hand, linear system analysis uses differential and difference equations
to represent time dependent or synchronous systems. A new extension of
Petri nets, called Global Petri Net (GPN) provides a means for combini...
Traditional dependence analysis techniques usually attempt to recognize the existence of dependencies between iterations of a loop and, in some cases, characterize these dependencies by finding direction vectors or distance vectors. A more general form of data dependence called hyperplane dependence is introduced. It is a dependence whose source an...
Several compile time transformations of loops with simple dependencies have been developed in order to expose possible parallelism in these loops. However, once an irregular data dependence is detected, no attempt is usually made to extract any parallel thread from the loop. In this paper, we present the parallel region execution, a new compile tim...
In a heterogeneous computing environment, computers have to use a
suitable transfer syntax to communicate with each other because of the
differences in internal data representations. Transfer syntax
conversions take over 90% of the total processing power needed in OSI
protocol processing. Application specific architectures in a
heterogeneous system...
This paper presents a methodology for designing folded VLSI
networks for implementing tensor-product forms. Using tensor-products
leads to very efficient expressions for a large number of computations
in digital signal processing and matrix arithmetic. The resulting
networks can trade-off total time delay with I/O bandwidth and chip
area. The main...
Initial investigations of Birch's outlier processing method (OPM)
have demonstrated an ability to extract a special class of
finite-duration signals from colored noise processes. This special class
of signals are low SNR signals whose shapes and latencies can vary
dramatically from trial to trial. Such signals, termed highly variable
events (HVE) i...
Partitioning the iteration space can significantly affect the execution time of a loop. The authors propose an improvement over previous partitioning methods for single loops with uniform data dependencies. For distributed memory systems, partitioning each loop separately does not guarantee an efficient execution of the code because of across loop...
Motion compensation is critical to successful topographic mapping,
with airborne interferometric SAR (InSAR). The pixel dependent phase
correction required depends upon the elevation of each scene patch,
which is initially unknown, requiring a flat Earth assumption. This
leads to terrain induced phase errors in the compressed data, but
accurate ele...
Processing SAR signal data into an image requires correlation with
a range-variant focussing operator. Current SAR processing algorithms
make approximations to the exact focussing operator, which causes a
noticeable degradation in image quality when the squint angle is large.
The difficulty arises from higher order phase terms in the operator
known...
The design of a parallel protocol processing system for a host system connected to an asynchronous transfer mode (ATM) network is described. Interesting aspects of the design are that the AAL5 adaptation layer is realized in hardware directly on the network adapter, and that the network adapter semetric interfaces to a multiprocessor using the proc...