Application-specific Information Research Articles

Channel, deadline, and distortion (C D2) aware scheduling for video streams over wireless

We study scheduling of multimedia traffic on the downlink of a wireless communication system. We examine a scenario where multimedia packets are associated with strict deadlines and are equivalent to lost packets if they arrive after their associated deadlines. Lost packets result in degradation of playout quality at the receiver, which is quantified in terms of the "distortion cost" associated with each packet. Our goal is to design a scheduler which minimizes the aggregate distortion cost over all receivers. We study the scheduling problem in a dynamic programming (DP) framework. Under well justified modeling reductions, we extensively characterize structural properties of the optimal control associated with the DP problem. We leverage these properties to design a low-complexity Channel, Deadline, and Distortion (CD <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) aware heuristic scheduling policy amenable to implementation in real wireless systems. We evaluate the performance of CD <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> via trace-driven simulations using H.264/MPEG-4 AVC coded video. Our experimental results show that CD <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> comfortably outperforms benchmark schedulers like earliest deadline first (EDF) and best channel first (BCF). CD <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> achieves these performance gains by using the knowledge of packet deadlines, wireless channel conditions, and application specific information (per-packet distortion costs) in a systematic and unified way for multimedia scheduling.

Low-Power Snoop Architecture for Synchronized Producer-Consumer Embedded Multiprocessing

We introduce a cross-layer customization methodology where application knowledge regarding data sharing in producer-consumer relationships is used in order to aggressively eliminate unnecessary and predictable snoop-induced cache lookups even for references to shared data, thus, achieving significant power reductions with minimal hardware cost. The technique exploits application-specific information regarding the exact producer-consumer relationships between tasks as well as information regarding the precise timing of synchronized accesses to shared memory buffers by their corresponding producers and/or consumers. Snoop-induced cache lookups for accesses to the shared data are eliminated when it is ensured that such lookups will not result in extra knowledge regarding the cache state in respect to the other caches and the memory. Our experiments show average power reductions of more than 80% compared to a general-purpose snoop protocol.

Edges, clearances, and wear: Little things that make big differences in bushing friction

Traditional pin-on-flat tribometers are necessary instruments for making direct measurements of tribological properties, but mechanical design of even simple systems often requires application-specific information that only component level testing can provide. This paper uses the design and operation of a bushing tribometer to elucidate geometric effects that plague bushing systems. For example, the nature of the bushing edge has a dramatic influence on the performance of the system in practice where the system is necessarily over-constrained. It is shown mathematically that the torque requirements increase as the wrap angle of the contact spreads for a constant friction coefficient; at steady state the equation for calculated torque requirement is found. This is demonstrated using ultra-high molecular weight polyethylene bushings that showed increasing torques at decreasing clearances. A polytetrafluoroethylene (PTFE) bushing with 150 μm interference initially required 50% more torque than a PTFE bushing with 350 μm clearance. As the two different bushings ran into steady state wear, the torque asymptotically approached the mathematically derived value. The results of these experiments provide designers insight into the design of successful bushing pairs and the ability to tune frictional torques without changing material through the selection of clearance.

Application Specific Routing Algorithms for Networks on Chip

In this paper we present a methodology to develop efficient and deadlock free routing algorithms for Network-on-Chip (NoC) platforms which are specialized for an application or a set of concurrent applications. The proposed methodology, called application specific routing algorithm (APSRA), exploits the application specific information regarding pairs of cores which communicate and other pairs which never communicate in the NoC platform to maximize communication adaptivity and performance. The methodology also exploits the known information regarding concurrency/non-concurrency of communication transactions among cores for the same purpose. We demonstrate, through analysis of adaptivity as well as simulation based evaluation of latency and throughput, that algorithms produced by the proposed methodology give significantly higher performance as compared to other deadlock free algorithms for both homogeneous as well as heterogeneous 2D mesh topology NoC systems. For example, for homogeneous mesh NoC, APSRA results in approximately 30% less average delay as compared to odd-even algorithm just below saturation load. Similarly the saturation load point for APSRA is significantly higher as compared to other adaptive routing algorithms for both homogeneous and non-homogeneous mesh networks.

Developing a Mobile GIS for Field Geospatial Data Acquisition

Field based and GPS assisted GIS are frequently used in various geoscience applications. Such systems deliver more advanced, time and cost effective tools than traditional field forms for information collection. At the same time, different systems are on the market. These systems mostly enable users to determine positions of geo-objects by GPS, and maintain functionalities to gather and analyze geometric information. The digital obtaining of the application's specific information is often underrepresented within these kinds of systems. This paper attempts to develop a system for gathering, integrating, analyzing, and visualizing spatial and aspatial information in electrical industry facilities. A PDA based GIS is extended to collect information in a beneficial manner, thus, adequately supporting the requirements of its users. Mobile GIS architectures, the components of a mobile GIS, and their impacts on gathering data are examined. The steps followed to design and develop a system for the electricity Transmission and Distribution Company are demonstrated. The results are presented and discussed in details in the paper.

Proactive Fuzzy Control and Adaptation Methods for Smart Homes

Proactive, context-aware computing isn't new. In 2000, David Tennenhouse called for a change in the boundary between the physical and virtual worlds. He identified proactive computing as an alternative to interactive computing and defined how future systems should become more involved with the real world. He also considered context-aware control systems with online adaptation especially promising. Today, ambient-intelligence researchers show increasing interest in both proactive applications and context-aware applications. Using different context-recognition methods, researchers can easily gather application-specific information from the environment and enable context-triggered actions. According to Hee Eon Byun and Keith Cheverst, a context-aware home can serve its inhabitants more flexibly and adaptively than an ordinary home. They also claim that proactive systems can be built using machine-learning algorithms with context recognition. In addition to context recognition, adaptivity is essential in intelligent environments. In terms of computing systems, the environment can adjust itself using adaptation mechanisms to comply with user preferences; it can become unobtrusive and better support user activities. A home adapting to its inhabitants' living style is much more convenient than a user adapting to the home's behavior. In this article, we show how to develop a proactive, adaptive, fuzzy home-control system, present the algorithm we used for adaptation, and evaluate the test results we obtained.

An open architecture for transport-level protocol coordination in distributed multimedia applications

We consider the problem of flow coordination in distributed multimedia applications. Most transport-level protocols are designed to operate independently and lack mechanisms for sharing information with other flows and coordinating data transport in various ways. This limitation becomes problematic in distributed applications that employ numerous flows between two computing clusters sharing the same intermediary forwarding path across the Internet. In this article, we propose an open architecture that supports the sharing of network state information, peer flow information, and application-specific information. Called simply the coordination protocol (CP) , the scheme facilitates coordination of network resource usage across flows belonging to the same application, as well as aiding other types of coordination. The effectiveness of our approach is illustrated in the context of multistreaming in 3D tele-immersion where consistency of network information across flows both greatly improves frame transport synchrony and minimizes buffering delay.

Dynamic Reconfiguration of Cache Indexing in Embedded Processors

Cache performance optimization is an important design consideration in building high-performance embedded processors. Unlike general-purpose microprocessors, embedded processors can take advantages of application-specific information in optimizing the cache performance. One of such examples is to use modified cache index bits (over conventional index bits) based on memory access traces from key target embedded applications so that the number of conflict misses can be reduced. In this paper, we present a novel fine-grained cache reconfiguration technique which allows an intra-program reconfiguration of cache index bits, thus better reflecting the changing characteristics of a program execution. The proposed technique, called dynamic reconfiguration of index bits (DRIB), dynamically changes cache index bits in the function level. This compiler-directed and fine-grained approach allows each function to be executed using its own optimal index bits with no additional hardware support. In order to avoid potential performance degradation by frequent cache invalidations from reconfiguring cache index bits, we describe an efficient algorithm for selecting target functions whose cache index bits are reconfigured. Our algorithm ensures that the number of cache misses reduced by DRIB outnumbers the number of cache misses increased from cache invalidations. We also propose a new cache architecture, Two-Level Indexing (TLI) cache, which further reduces the number of conflict misses by intelligently dividing indexing steps into two stages. Our experimental results show that the DRIP approach combined with the TLI cache reduces the number of cache misses by 35% over the conventional cache indexing technique.

System for remote evaluation of ultrasound information obtained by a programmed application-specific data collection device

A system which includes at least one ultrasound data collection device which is programmable to carry out a specific ultrasound procedure on a selected part of a human body of a patient. The resulting ultrasound data is transmitted via a local server at the site of the data collection device to the internet and from there to a web database server which processes the raw ultrasound data and provides application-specific information, such as a three-dimensional model, which can be used for diagnostic interpretation of the body part imaged by the ultrasound suitable for use in the treatment of the patient.

Reducing Conflict Misses by Application-Specific Reconfigurable Indexing

The predictability of memory access patterns in embedded systems can be successfully exploited to devise effective application-specific cache optimizations. In this paper, an improved indexing scheme for direct-mapped caches, which drastically reduces the number of conflict misses by using application-specific information, is proposed. The indexing scheme is based on the selection of a subset of the address bits. With respect to similar approaches, the solution has two main strengths. First, owing to an analytical model for the conflict-miss conditions of a given trace, it provides a symbolic algorithm to compute the optimum solution (i.e., the subset of address bits to be used as cache index that minimize the number of conflict misses). Second, owing to a reconfigurable bit selector that can be programmed at run time, it allows the optimal cache indexing to fit to a given application. Results show an average reduction of conflict misses of 24%, measured over a set of standard benchmarks, and for different cache configurations

Detecting Application-Level Failures in Component-Based Internet Services

Most Internet services (e-commerce, search engines, etc.) suffer faults. Quickly detecting these faults can be the largest bottleneck in improving availability of the system. We present Pinpoint, a methodology for automating fault detection in Internet services by: 1) observing low-level internal structural behaviors of the service; 2) modeling the majority behavior of the system as correct; and 3) detecting anomalies in these behaviors as possible symptoms of failures. Without requiring any a priori application-specific information, Pinpoint correctly detected 89%-96% of major failures in our experiments, as compared with 20%-70% detected by current application-generic techniques.

A reprogrammable customization framework for efficient branch resolution in embedded processors

We present a customization framework for embedded processors which employs the utilization of application-specific information, thus specializing the processor's microarchitecture to the application needs. The increased processor utilization leads to a low-cost system implementation with no sacrifice in performance requirements and to reduced custom hardware in a typical SOC. We illustrate these ideas through the branch resolution problem, known to impose severe performance degradation on control-dominated embedded applications. A customization approach for early branch resolution and subsequent folding is presented. The application-specific information is captured by the microarchitecture through a low-cost reprogrammable hardware, thus attaining the twin benefits of processor standardization and application-specific customization. Experimental results show that for a representative set of control-dominated applications a reduction in the range of 3--22% in processor cycles can be achieved, thus extending the scope of low-cost embedded processors in complex codesigns for control intensive systems.

Low-power branch target buffer for application-specific embedded processors

A methodology for a low-power branch identification mechanism which enables the design of extremely power-efficient branch predictors for embedded processors is presented. The proposed technique utilises application-specific information regarding the control-flow structure of the program&apos;s major loops. Such information is used to completely eliminate the power hungry branch target buffer (BTB) lookups which normally occur at every execution cycle. Exact application knowledge regarding the control-flow structure of the program obviates the power expensive BTB operations, thus enabling the utilisation of contemporary branch predictors in high-end, yet power-sensitive embedded processors. The utilisation of exact application knowledge results not only in the complete elimination of the power hungry BTB structure but also in a perfect branch and target address identification. A cost-efficient and programmable hardware architecture for capturing the control-flow structure of the program is presented. The hardware complexity of the proposed architecture is carefully analysed in terms of power, performance and area overhead. The proposed technique delivers power reductions in excess of 90% for a set of representative embedded benchmarks.

Developing Custom Tools for Deriving Complex Data from Travel Survey Databases

Data from large-scale travel survey databases, such as the Nationwide Personal Transportation Survey (NPTS) and the National Household Travel Survey (NHTS), are often used to derive complex parameters for transportation modeling applications not originally targeted by the surveys. When situations demand complex data manipulation tasks, publicly available tools for the purpose do not obviate the need for data users to sift through entire databases and develop custom solutions. This paper presents a flexible methodology for developing custom database tools for cost-effectively deriving application-specific information from travel survey data. The seven-step methodology accounts for assessment of needs, verification of validity of travel survey data to the application, establishment of scientific justification, development of functional requirements of the system, development of data model, definition of processes, and development and testing of tools. To demonstrate the methodology, a case study involving derivation of locality-specific parameters for emission factor models from the NPTS and NHTS databases is presented. With the use of this methodology, a custom database application called Travel-Related Inputs Model for MOBILE6.x (TRIMM) was developed for this case study. The working mechanisms of TRIMM are illustrated. The methodology outlined, though specific to travel survey databases, is sufficiently generic to be used for developing custom tools to derive various modeling parameters from large transportation databases.

Developing Custom Tools for Deriving Complex Data from Travel Survey Databases

Data from large-scale travel survey databases, such as the Nationwide Personal Transportation Survey (NPTS) and the National Household Travel Survey (NHTS), are often used to derive complex parameters for transportation modeling applications not originally targeted by the surveys. When situations demand complex data manipulation tasks, publicly available tools for the purpose do not obviate the need for data users to sift through entire databases and develop custom solutions. This paper presents a flexible methodology for developing custom database tools for cost-effectively deriving application-specific information from travel survey data. The seven-step methodology accounts for assessment of needs, verification of validity of travel survey data to the application, establishment of scientific justification, development of functional requirements of the system, development of data model, definition of processes, and development and testing of tools. To demonstrate the methodology, a case study involving derivation of locality-specific parameters for emission factor models from the NPTS and NHTS databases is presented. With the use of this methodology, a custom database application called Travel-Related Inputs Model for MOBILE6.x (TRIMM) was developed for this case study. The working mechanisms of TRIMM are illustrated. The methodology outlined, though specific to travel survey databases, is sufficiently generic to be used for developing custom tools to derive various modeling parameters from large transportation databases.

Adapting applications in handheld devices using fuzzy context information

Context-aware devices are able to take advantage of fusing sensory and application specific information to provide proper information on a situation, for more flexible services, and adaptive user interfaces (UI). It is characteristic for handheld devices and their users that they are continuously moving in several simultaneous fuzzy contexts. The dynamic environment sets special requirements for usability and acceptance of context-aware applications. Context-aware applications must be able to operate sensibly even if the context recognition is not 100% reliable and there are multiple contexts present at the same time. We present an approach for controlling context-aware applications in the case of multiple fuzzy contexts. This work has several potential applications in the area of adaptive UI application control. Our study is focused on the adaptation of applications representing information in handheld devices. The design of controllers and experiments with real context data from user scenarios are presented. Experimental results show that the proposed approach enhances the capability of adapting information representation in a handheld device. User reactions indicate that they accept application adaptation in many situations while insisting on retaining the most control over their device. Moreover, user feedback indicates that abrupt adaptations and instability should be avoided in the application control.

Satellite image fusion with multiscale wavelet analysis for marine applications: preserving spatial information and minimizing artifacts (PSIMA)

Image fusion has many diverse purposes. There is no universal, quantitative performance measure to estimate image fusion quality. An essential principle is that the original application-specific information is preserved while artifacts are minimized in the final product. As an application of wavelet analysis to the fusion of images with significantly different spectral properties and pixel spacings, we propose a method that is based on multiscale wavelet analysis, thus preserving spatial information and minimizing artifacts (PSIMA). The information content of the two images is emphasized. With the PSIMA method, the images are fused while minimizing the degree of resampling. Therefore, the finest spatial information in the input images can be preserved and artifacts minimized in the fused product, independent of the fusion method. We demonstrate the PSIMA method using RADARSAT-1 scanning synthetic aperture radar (ScanSAR) and National Oceanic and Atmospheric Administration advanced very high resolution radiometer (NOAA AVHRR) images. This marine data set is a precursor to contemporaneous SAR and electro-optical data that will be available from the advanced synthetic aperture radar (ASAR) and medium-resolution imaging spectrometer (MERIS) sensors on the environmental satellite (ENVISAT). The results show that the PSIMA method is superior to conventional image fusion methods in terms of spatial information preservation and artifact rejection.

RELATIONAL DEDUCTIVE OBJECT-ORIENTED MODELING (RDOOM) APPROACH FOR FINDING, REPRESENTING AND INTEGRATING APPLICATION-SPECIFIC CONCEPTS

Next generation information systems (NGISs) have to support the manipulation of data-oriented, behavioral and deductive aspects of application domains. Many modeling methods, e.g. UML and other object-oriented modeling methods offer primitives for modeling data-oriented and behavioral aspects but they do not support the modeling of deductive aspects. In addition, NGISs may be implemented by several separate software/database systems that are based on different paradigms. Therefore it is not appropriate to use such a modeling method which is based on one paradigm. In NGISs it is essential to integrate the value-oriented approach with the object-oriented approach. We develop a relational deductive object-oriented modeling (RDOOM) approach for NGISs. Our goal is to combine into one modeling method, the navigation power of the relational model, the modeling power of the object-orientation and the inference power of the deductive (logical) framework. It is obvious that in NGISs complex and large specifications have to be embedded in application-specific concepts and structures that are defined beforehand for users to facilitate their query formulation. The detection and specification of application-specific concepts and structures means a new challenge for analysis methods. We show that on the basis of the primitives of RDOOM it is possible to represent this kind of application-specific information in a natural way. It is also necessary that the appropriateness and adequacy of application-specific concepts and structures can be tested before their expensive design and implementation phases. For the definition of these concepts and structures a diagrammatic representation typical of many modeling methods is not sufficient. Rather, a precise and executable representation is needed. Especially the complex and large derivation rules behind deductive concepts cannot be expressed precisely with diagrammatic representations. We develop set-theoretical representations for our primitives. The precise representation of the result of systems analysis also gives a more substantial starting point for the design and implementation of NGISs.

Customized Message Passing

Replacing traditional operating systems communication implementations with customized implementations increases the performance of parallel and distributed applications. This paper describes the design and implementation of customizable message passing systems. The customized message passing systems are generated using application-specific information such as the profile of an application's communication pattern. FFT, Simplex, and Cholesky are used as example parallel applications. The message passing system has also been customized for different types of distributed system services including a distributed scheduling facility. The customized message passing system likewise improves the performance of these facilities and enhances their scalability. As a practical concern, as there are a large number of possible optimizations, object-oriented frameworks are employed to organize the implementations and to facilitate the choice of optimizations.

An efficient network architecture motivated by application-level QoS

We consider application-level quality of service (QoS) requirements in design of networks that provide delay and loss guarantees. Using this approach, we have designed a novel network architecture that in many aspects is more efficient than ones motivated exclusively by packet QoS. An overview of our work is presented in this paper. The centerpiece of our design is a traffic model that enables delivery of application specific information to the network. Based on the traffic model, we have developed (i) efficient network techniques for providing application-level delay guarantees, (ii) an admission control algorithm for a statistical service that bounds application data losses below a specified value, and (iii) network techniques for managing application data losses to achieve fairness and protection of high priority data units marked by applications (e.g., I frames of MPEG applications).