Fonte: Institute of Electrical and Electronics Engineers - IEEE; International Association for Computer and Information Science - ACIS; TaiyuanPublicador: Institute of Electrical and Electronics Engineers - IEEE; International Association for Computer and Information Science - ACIS; Taiyuan
Recommender Systems have been studied and developed as an indispensable technique of the Information Filtering field. A drawback of traditional user-item systems is that most recommenders ignore connections consistent with the real world recommendations. Furthermore, trust-based approaches ignore the group modeling and do not respect the users’ individualities in a group recommendation set. In this paper, we propose a conceptual architecture which uses the social trust consensus from users to improve the accuracy of the trust-based recommender systems. It is based on an existent model and integrates user’s trust relations and item’s factors into a generic latent fator model. One advantage of our model is the possibility to bias the users’ similarity computation according to a trust consensus that assists in the formation of groups, such as the group of individuals who share the same content. The proposal representes the first steps towards the development of a group recommender system model. We provide an evaluation of our method with the Epinions dataset and compare our approach against other state-of-the-art techniques.; CAPES; CNPq; FAPESP
Human-robot interaction is now well enough understood to allow us to build useful systems that can function outside of the laboratory. This thesis defines sociable robot system in the context of long-term interaction, proposes guidelines for creating and evaluating such systems, and describes the implementation of a robot that has been designed to help individuals effect behavior change while dieting. The implemented system is a robotic weight loss coach, which is compared to a standalone computer and to a traditional paper log in a controlled study. A current challenge in weight loss is in getting individuals to keep off weight that is lost. The results of our study show that participants track their calorie consumption and exercise for nearly twice as long when using the robot than with the other methods and develop a closer relationship with the robot. Both of these are indicators of longer-term success at weight loss and maintenance.; by Cory David Kidd.; Thesis (Ph. D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2008.; Includes bibliographical references (p. 241-251).
Today, modern System-on-a-Chip (SoC) systems have grown rapidly due to the increased processing power, while maintaining the size of the hardware circuit. The number of transistors on a chip continues to increase, but current SoC designs may not be able to exploit the potential performance, especially with energy consumption and chip area becoming two major concerns. Traditional SoC designs usually separate software and hardware. Thus, the process of improving the system performance is a complicated task for both software and hardware designers. The aim of this research is to develop hardware acceleration workflow for software applications. Thus, system performance can be improved with constraints of energy consumption and on-chip resource costs. The characteristics of software applications can be identified by using profiling tools. Hardware acceleration can have significant performance improvement for highly mathematical calculations or repeated functions. The performance of SoC systems can then be improved, if the hardware acceleration method is used to accelerate the element that incurs performance overheads. The concepts mentioned in this study can be easily applied to a variety of sophisticated software applications.
The contributions of SoC-based hardware acceleration in the hardware-software co-design platform include the following: (1) Software profiling methods are applied to H.264 Coder-Decoder (CODEC) core. The hotspot function of aimed application is identified by using critical attributes such as cycles per loop...
For the past several decades, we have experienced the tremendous growth, in both scale and scope, of real-time embedded systems, thanks largely to the advances in IC technology. However, the traditional approach to get performance boost by increasing CPU frequency has been a way of past. Researchers from both industry and academia are turning their focus to multi-core architectures for continuous improvement of computing performance. In our research, we seek to develop efficient scheduling algorithms and analysis methods in the design of real-time embedded systems on multi-core platforms. Real-time systems are the ones with the response time as critical as the logical correctness of computational results. In addition, a variety of stringent constraints such as power/energy consumption, peak temperature and reliability are also imposed to these systems. Therefore, real-time scheduling plays a critical role in design of such computing systems at the system level.
We started our research by addressing timing constraints for real-time applications on multi-core platforms, and developed both partitioned and semi-partitioned scheduling algorithms to schedule fixed priority, periodic, and hard real-time tasks on multi-core platforms. Then we extended our research by taking temperature constraints into consideration. We developed a closed-form solution to capture temperature dynamics for a given periodic voltage schedule on multi-core platforms...
Scientific exploration demands heavy usage of computational resources for large-scale and deep analysis in many different fields. The complexity or the sheer scale of the computational studies can sometimes be encapsulated in the form of a workflow that is made up of numerous dependent components. Due to its decomposable and parallelizable nature, different components of a scientific workflow may be mapped over a distributed resource infrastructure to reduce time to results. However, the resource infrastructure may be heterogeneous, dynamic, and under diverse administrative control. Workflow management tools are utilized to help manage and deal with various aspects in the lifecycle of such complex applications. One particular and fundamental aspect that has to be dealt with as smooth and efficient as possible is the run-time coordination of workflow activities (i.e. workflow orchestration). Our efforts in this study are focused on improving the workflow orchestration process in such dynamic and distributed resource environments. We tackle three main aspects of this process and provide contributions in each of them. Our first contribution involves increasing the scalability and site autonomy in situations where the mapped components of a workflow span across several heterogeneous administrative domains. We devise and implement a generic decentralization framework for orchestration of workflows under such conditions. Our second contribution is involved with addressing the issues that arise due to the dynamic nature of such environments. We provide generic adaptation mechanisms that are highly transparent and also substantially less intrusive with respect to the rest of the workflow in execution. Our third contribution is to improve the efficiency of orchestration of large-scale parameter-sweep workflows. By exploiting their specific characteristics...
http://dx.doi.org/10.1016/j.procs.2013.09.273; This paper proses a formal modeling approach for predicting emergent reactive systems and system of systems (SoS) behaviors resulting from the interactions among subsystems and among the system and its environment. The approach emphasizes specification of component behavior and component interaction as separate concerns at the architectural level, consistent with well-accepted definitions of SoS. The Monterey Phoenix (MP) approach provides features for production of emergent SoS behaviors. An example highlights limitations of current modeling languages and approaches that hinder prediction of emergent behavior, an demonstrates how the application of MP can enhance SoS modeling capability through the following principles: Model component interactions as general rules, orthogonal to the component behavior. Automatically extract possible scenarios (use cases) from descriptions of system behavior. Test system behavior against stakeholder expectations/requirements using scenario inspection and assertion checking. MP provides a new capability for automatically verifying system behaviora early in the lifecycle, when design flaws are most easily and inexpensively corrected. MP extends existing frameworks and allows multiple visualizations for different stakeholders...
This paper proposes a new architecture targeting real-time and reliable
Distributed Computer-Controlled Systems (DCCS). This architecture provides a
structured approach for the integration of soft and/or hard real-time applications
with Commercial O -The-Shelf (COTS) components. The Timely Computing Base
model is used as the reference model to deal with the heterogeneity of system
components with respect to guaranteeing the timeliness of applications. The reliability
and availability requirements of hard real-time applications are guaranteed by a
software-based fault-tolerance approach.; FCT
Multiple-input multiple-output (MIMO) wireless transmission imposes huge
challenges on the design of efficient hardware architectures for iterative
receivers. A major challenge is soft-input soft-output (SISO) MIMO demapping,
often approached by sphere decoding (SD). In this paper, we introduce the - to
our best knowledge - first VLSI architecture for SISO SD applying a single
tree-search approach. Compared with a soft-output-only base architecture
similar to the one proposed by Studer et al. in IEEE J-SAC 2008, the
architectural modifications for soft input still allow a one-node-per-cycle
execution. For a 4x4 16-QAM system, the area increases by 57% and the operating
frequency degrades by 34% only.; Comment: Accepted for IEEE Transactions on Circuits and Systems II Express
Briefs, May 2010. This draft from April 2010 will not be updated any more.
Please refer to IEEE Xplore for the final version. *) The final publication
will appear with the modified title "A Scalable VLSI Architecture for
Soft-Input Soft-Output Single Tree-Search Sphere Decoding"
Technical advances in ubiquitous sensing, embedded computing, and wireless
communication are leading to a new generation of engineered systems called
cyber-physical systems (CPS). CPS promises to transform the way we interact
with the physical world just as the Internet transformed how we interact with
one another. Before this vision becomes a reality, however, a large number of
challenges have to be addressed. Network quality of service (QoS) management in
this new realm is among those issues that deserve extensive research efforts.
It is envisioned that wireless sensor/actuator networks (WSANs) will play an
essential role in CPS. This paper examines the main characteristics of WSANs
and the requirements of QoS provisioning in the context of cyber-physical
computing. Several research topics and challenges are identified. As a sample
solution, a feedback scheduling framework is proposed to tackle some of the
identified challenges. A simple example is also presented that illustrates the
effectiveness of the proposed solution.; Comment: To appear in The 2008 Int.Conf. on Embedded Software and Systems
(ICESS), Chengdu, China, July 2008
Quantitative aspects of computation are important and sometimes essential in
characterising the behavior and determining the properties of systems. They are
related to the use of physical quantities (storage space, time, bandwidth,
etc.) as well as mathematical quantities (e.g. probability and measures for
reliability, security and trust). Such quantities play a central role in
defining both the model of systems (architecture, language design, semantics)
and the methodologies and tools for the analysis and verification of system
properties. The aim of this workshop is to discuss the explicit use of
quantitative information such as time and probabilities either directly in the
model or as a tool for the analysis of systems.
This volume contains the proceedings of the Tenth Workshop on Quantitative
Aspects of Programming Languages (QAPL 2012), held in Tallin, Estonia, on March
31 and April 1, 2012. QAPL 2012 is a satellite event of the European Joint
Conferences on Theory and Practice of Software (ETAPS 2012). The workshop theme
is on quantitative aspects of computation. These aspects are related to the use
of physical quantities (storage space, time, bandwidth, etc.) as well as
mathematical quantities (e.g. probability and measures for reliability,
security and trust), and play an important (sometimes essential) role in
characterising the behavior and determining the properties of systems. Such
quantities are central to the definition of both the model of systems
(architecture, language design, semantics) and the methodologies and tools for
the analysis and verification of the systems properties. The aim of this
workshop is to discuss the explicit use of quantitative information such as
time and probabilities either directly in the model or as a tool for the
analysis of systems.; Comment: EPTCS 85, 2012
We propose a novel and natural architecture for decentralized control that is
applicable whenever the underlying system has the structure of a partially
ordered set (poset). This controller architecture is based on the concept of
Moebius inversion for posets, and enjoys simple and appealing separation
properties, since the closed-loop dynamics can be analyzed in terms of
decoupled subsystems. The controller structure provides rich and interesting
connections between concepts from order theory such as Moebius inversion and
control-theoretic concepts such as state prediction, correction, and
separability. In addition, using our earlier results on H_2-optimal
decentralized control for arbitrary posets, we prove that the H_2-optimal
controller in fact possesses the proposed structure, thereby establishing the
optimality of the new controller architecture.; Comment: 32 pages, 9 figures, submitted to IEEE Transactions on Automatic
The beginning of the 21st century has seen many projects on distributed hash
tables, both research and commercial. One of their aims has been to replace the
first generation of file sharing software with scalable peer-to-peer
architectures. On other fronts, the same techniques are applied, for example,
to content delivery networks, streaming networks, cooperative caches,
distributed file systems, and grid computing architectures for scientific use.
This trend has emerged because with cooperative peers it is possible to
asymptotically enhance the use of resouces in sharing of data compared to the
basic client-server architecture.
The need for distribution of data is wide and one could argue that it is as
fundamental a building block as the message passing of the Internet. As an
answer to this need a new scalable architecture is introduced: Hybrid
Communication Architecture (HCA), which provides both data sharing and message
passing as communication primitives for applications. HCA can be regarded as an
abstraction layer for communication which is further encapsulated by a
higher-level middleware. HCA is aimed at general use, and it is not designed
for any particular application. One key idea is to combine data sharing with
streaming since together they enable many applications not easily implementable
with only one of these features. For example...
This volume contains the proceedings of the Twelfth Workshop on Quantitative
Aspects of Programming Languages and Systems (QAPL 2014), held in Grenoble,
France, on 12 and 13 April, 2014. QAPL 2014 was a satellite event of the
European Joint Conferences on Theory and Practice of Software (ETAPS). The
central theme of the workshop is that of quantitative aspects of computation.
These aspects are related to the use of physical quantities (storage space,
time, bandwidth, etc.) as well as mathematical quantities (e.g. probability and
measures for reliability, security and trust), and play an important (sometimes
essential) role in characterising the behaviour and determining the properties
of systems. Such quantities are central to the definition of both the model of
systems (architecture, language design, semantics) and the methodologies and
tools for the analysis and verification of the systems properties. The aim of
this workshop is to discuss the explicit use of quantitative information such
as time and probabilities either directly in the model or as a tool for the
analysis of systems.
This paper deals with denial of service attack. Overview of the existing
attacks and methods is proposed. Classification scheme is presented for a
different denial of service attacks. There is considered agent-based intrusion
detection systems architecture. Considered main components and working
principles for a systems of such kind.; Comment: 6 pages, 3 figures
Optimal resource allocation is of paramount importance in utilizing the
scarce radio spectrum efficiently and provisioning quality of service for
miscellaneous user applications, generating hybrid data traffic streams in
present-day wireless communications systems. A dynamism of the hybrid traffic
stemmed from concurrently running mobile applications with temporally varying
usage percentages in addition to subscriber priorities impelled from network
providers' perspective necessitate resource allocation schemes assigning the
spectrum to the applications accordingly and optimally. This manuscript
concocts novel centralized and distributed radio resource allocation
optimization problems for hybrid traffic-conveying cellular networks
communicating users with simultaneously running multiple delay-tolerant and
real-time applications modelled as logarithmic and sigmoidal utility functions,
volatile application percent usages, and diverse subscriptions. Casting under a
utility proportional fairness entail no lost calls for the proposed modi
operandi, for which we substantiate the convexity, devise computationally
efficient algorithms catering optimal rates to the applications, and prove a
mutual mathematical equivalence. Ultimately, the algorithms performance is
evaluated via simulations and discussing germane numerical results.
During its execution, a task is independent of all other tasks. For an
application which executes in terms of tasks, the application definition can be
free of the details of the execution. Many projects have demonstrated that a
task system (TS) can provide such an application with a parallel, distributed,
heterogeneous, adaptive, dynamic, real-time, interactive, reliable, secure or
other execution. A task consists of items and thus the application is defined
in terms of items. An item architecture (IA) can support arrays, routines and
other structures of items, thus allowing for a structured application
definition. Taking properties from many projects, the support can extend
through to currying, application defined types, conditional items, streams and
other definition elements. A task system and item architecture (TSIA) thus
promises unprecedented levels of support for application execution and
definition.; Comment: vii+244 pages, including 126 figures of diagrams and code examples.
Submitted to Springer Verlag. For further information see http://www.tsia.org
One of the most demanding challenges for the designers of parallel computing
architectures is to deliver an efficient network infrastructure providing low
latency, high bandwidth communications while preserving scalability. Besides
off-chip communications between processors, recent multi-tile (i.e. multi-core)
architectures face the challenge for an efficient on-chip interconnection
network between processor's tiles. In this paper, we present a configurable and
scalable architecture, based on our Distributed Network Processor (DNP) IP
Library, targeting systems ranging from single MPSoCs to massive HPC platforms.
The DNP provides inter-tile services for both on-chip and off-chip
communications with a uniform RDMA style API, over a multi-dimensional direct
network with a (possibly) hybrid topology.; Comment: 8 pages, 11 figures, submitted to Hot Interconnect 2009
We present a generic and flexible architecture to realize CloudNets: virtual
networks connecting cloud resources with resource guarantees. Our architecture
is federated and supports different (and maybe even competing) economical
roles, by providing explicit negotiation and provisioning interfaces.
Contract-based interactions and a resource description language that allows for
aggregation and abstraction, preserve the different roles' autonomy without
sacrificing flexibility. Moreover, since our CloudNet architecture is plugin
based, essentially all cloud operating systems (e.g., OpenStack) or link
technologies (e.g., VLANs, OpenFlow, VPLS) can be used within the framework.
This paper describes two roles in more detail: The Physical Infrastructure
Providers (PIP) which own the substrate network and resources, and the Virtual
Network Providers (VNP) which can act as resource and CloudNet brokers and
resellers. Both roles are fully implemented in our wide-area prototype that
spans remote sites and resources.
The "Disaggregated Server" concept has been proposed for datacenters where
the same type server resources are aggregated in their respective pools, for
example a compute pool, memory pool, network pool, and a storage pool. Each
server is constructed dynamically by allocating the right amount of resources
from these pools according to the workload's requirements. Modularity, higher
packaging and cooling efficiencies, and higher resource utilization are among
the suggested benefits. With the emergence of very large datacenters, "clouds"
containing tens of thousands of servers, datacenter efficiency has become an
important topic. Few computer chip and systems vendors are working on and
making frequent announcements on silicon photonics and disaggregated memory
In this paper we study the trade-off between cost and performance of building
a disaggregated memory system where DRAM modules in the datacenter are pooled,
for example in memory-only chassis and racks. The compute pool and the memory
pool are interconnected by an optical interconnect to overcome the distance and
bandwidth issues of electrical fabrics. We construct a simple cost model that
includes the cost of latency, cost of bandwidth and the savings expected from a
disaggregated memory system. We then identify the level at which a
disaggregated memory system becomes cost competitive with a traditional direct
attached memory system.
Our analysis shows that a rack-scale disaggregated memory system will have a
non-trivial performance penalty...