300,362 research outputs found
Micro protocol engineering for unstructured carriers: On the embedding of steganographic control protocols into audio transmissions
Network steganography conceals the transfer of sensitive information within
unobtrusive data in computer networks. So-called micro protocols are
communication protocols placed within the payload of a network steganographic
transfer. They enrich this transfer with features such as reliability, dynamic
overlay routing, or performance optimization --- just to mention a few. We
present different design approaches for the embedding of hidden channels with
micro protocols in digitized audio signals under consideration of different
requirements. On the basis of experimental results, our design approaches are
compared, and introduced into a protocol engineering approach for micro
protocols.Comment: 20 pages, 7 figures, 4 table
Evaluation of A Resilience Embedded System Using Probabilistic Model-Checking
If a Micro Processor Unit (MPU) receives an external electric signal as
noise, the system function will freeze or malfunction easily. A new resilience
strategy is implemented in order to reset the MPU automatically and stop the
MPU from freezing or malfunctioning. The technique is useful for embedded
systems which work in non-human environments. However, evaluating resilience
strategies is difficult because their effectiveness depends on numerous,
complex, interacting factors.
In this paper, we use probabilistic model checking to evaluate the embedded
systems installed with the above mentioned new resilience strategy. Qualitative
evaluations are implemented with 6 PCTL formulas, and quantitative evaluations
use two kinds of evaluation. One is system failure reduction, and the other is
ADT (Average Down Time), the industry standard. Our work demonstrates the
benefits brought by the resilience strategy. Experimental results indicate that
our evaluation is cost-effective and reliable.Comment: In Proceedings ESSS 2014, arXiv:1405.055
Developing a distributed electronic health-record store for India
The DIGHT project is addressing the problem of building a scalable and highly available information store for the Electronic Health Records (EHRs) of the over one billion citizens of India
Efficient Simulation of Structural Faults for the Reliability Evaluation at System-Level
In recent technology nodes, reliability is considered a part of the standard design Âżow at all levels of embedded system design. While techniques that use only low-level models at gate- and register transfer-level offer high accuracy, they are too inefficient to consider the overall application of the embedded system. Multi-level models with high abstraction are essential to efficiently evaluate the impact of physical defects on the system. This paper provides a methodology that leverages state-of-the-art techniques for efficient fault simulation of structural faults together with transaction-level modeling. This way it is possible to accurately evaluate the impact of the faults on the entire hardware/software system. A case study of a system consisting of hardware and software for image compression and data encryption is presented and the method is compared to a standard gate/RT mixed-level approac
A Route Confidence Evaluation Method for Reliable Hierarchical Text Categorization
Hierarchical Text Categorization (HTC) is becoming increasingly important
with the rapidly growing amount of text data available in the World Wide Web.
Among the different strategies proposed to cope with HTC, the Local Classifier
per Node (LCN) approach attains good performance by mirroring the underlying
class hierarchy while enforcing a top-down strategy in the testing step.
However, the problem of embedding hierarchical information (parent-child
relationship) to improve the performance of HTC systems still remains open. A
confidence evaluation method for a selected route in the hierarchy is proposed
to evaluate the reliability of the final candidate labels in an HTC system. In
order to take into account the information embedded in the hierarchy, weight
factors are used to take into account the importance of each level. An
acceptance/rejection strategy in the top-down decision making process is
proposed, which improves the overall categorization accuracy by rejecting a few
percentage of samples, i.e., those with low reliability score. Experimental
results on the Reuters benchmark dataset (RCV1- v2) confirm the effectiveness
of the proposed method, compared to other state-of-the art HTC methods
Techniques for the Fast Simulation of Models of Highly dependable Systems
With the ever-increasing complexity and requirements of highly dependable systems, their evaluation during design and operation is becoming more crucial. Realistic models of such systems are often not amenable to analysis using conventional analytic or numerical methods. Therefore, analysts and designers turn to simulation to evaluate these models. However, accurate estimation of dependability measures of these models requires that the simulation frequently observes system failures, which are rare events in highly dependable systems. This renders ordinary Simulation impractical for evaluating such systems. To overcome this problem, simulation techniques based on importance sampling have been developed, and are very effective in certain settings. When importance sampling works well, simulation run lengths can be reduced by several orders of magnitude when estimating transient as well as steady-state dependability measures. This paper reviews some of the importance-sampling techniques that have been developed in recent years to estimate dependability measures efficiently in Markov and nonMarkov models of highly dependable system
Safety Evaluation of Critical Applications Distributed on TDMA-Based Networks
Critical embedded systems have to provide a high level of dependability. In
automotive domain, for example, TDMA protocols are largely recommended because
of their deterministic behavior. Nevertheless, under the transient
environmental perturbations, the loss of communication cycles may occur with a
certain probability and, consequently, the system may fail. This paper analyzes
the impact of the transient perturbations (especially due to Electromagnetic
Interferences) on the dependability of systems distributed on TDMA-based
networks. The dependability of such system is modeled as that of
"consecutive-k-out-of-n:F" systems and we provide a efficient way for its
evaluation
Methods of Technical Prognostics Applicable to Embedded Systems
HlavnĂ cĂlem dizertace je poskytnutĂ ucelenĂ©ho pohledu na problematiku technickĂ© prognostiky, kterĂĄ nachĂĄzĂ uplatnÄnĂ v tzv. prediktivnĂ ĂșdrĆŸbÄ zaloĆŸenĂ© na trvalĂ©m monitorovĂĄnĂ zaĆĂzenĂ a odhadu ĂșrovnÄ degradace systĂ©mu Äi jeho zbĂœvajĂcĂ ĆŸivotnosti a to zejmĂ©na v oblasti komplexnĂch zaĆĂzenĂ a strojĆŻ. V souÄasnosti je technickĂĄ diagnostika pomÄrnÄ dobĆe zmapovanĂĄ a reĂĄlnÄ nasazenĂĄ na rozdĂl od technickĂ© prognostiky, kterĂĄ je stĂĄle rozvĂjejĂcĂm se oborem, kterĂœ ovĆĄem postrĂĄdĂĄ vÄtĆĄĂ mnoĆŸstvĂ reĂĄlnĂœch aplikaci a navĂc ne vĆĄechny metody jsou dostateÄnÄ pĆesnĂ© a aplikovatelnĂ© pro embedded systĂ©my. DizertaÄnĂ prĂĄce pĆinĂĄĆĄĂ pĆehled zĂĄkladnĂch metod pouĆŸitelnĂœch pro ĂșÄely predikce zbĂœvajĂcĂ uĆŸitnĂ© ĆŸivotnosti, jsou zde popsĂĄny metriky pomocĂ, kterĂœch je moĆŸnĂ© jednotlivĂ© pĆĂstupy porovnĂĄvat aĆ„ uĆŸ z pohledu pĆesnosti, ale takĂ© i z pohledu vĂœpoÄetnĂ nĂĄroÄnosti. Jedno z dizertaÄnĂch jader tvoĆĂ doporuÄenĂ a postup pro vĂœbÄr vhodnĂ© prognostickĂ© metody s ohledem na prognostickĂĄ kritĂ©ria. DalĆĄĂm dizertaÄnĂm jĂĄdrem je pĆedstavenĂ tzv. ÄĂĄsticovĂ©ho filtrovanĂ (particle filtering) vhodnĂ© pro model-based prognostiku s ovÄĆenĂm jejich implementace a porovnĂĄnĂm. HlavnĂ dizertaÄnĂ jĂĄdro reprezentuje pĆĂpadovou studii pro velmi aktuĂĄlnĂ tĂ©ma prognostiky Li-Ion baterii s ohledem na trvalĂ© monitorovĂĄnĂ. PĆĂpadovĂĄ studie demonstruje proces prognostiky zaloĆŸenĂ© na modelu a srovnĂĄvĂĄ moĆŸnĂ© pĆĂstupy jednak pro odhad doby pĆed vybitĂm baterie, ale takĂ© sleduje moĆŸnĂ© vlivy na degradaci baterie. SouÄĂĄstĂ prĂĄce je zĂĄkladnĂ ovÄĆenĂ modelu Li-Ion baterie a nĂĄvrh prognostickĂ©ho procesu.The main aim of the thesis is to provide a comprehensive overview of technical prognosis, which is applied in the condition based maintenance, based on continuous device monitoring and remaining useful life estimation, especially in the field of complex equipment and machinery. Nowadays technical prognosis is still evolving discipline with limited number of real applications and is not so well developed as technical diagnostics, which is fairly well mapped and deployed in real systems. Thesis provides an overview of basic methods applicable for prediction of remaining useful life, metrics, which can help to compare the different approaches both in terms of accuracy and in terms of computational/deployment cost. One of the research cores consists of recommendations and guide for selecting the appropriate forecasting method with regard to the prognostic criteria. Second thesis research core provides description and applicability of particle filtering framework suitable for model-based forecasting. Verification of their implementation and comparison is provided. The main research topic of the thesis provides a case study for a very actual Li-Ion battery health monitoring and prognostics with respect to continuous monitoring. The case study demonstrates the prognostic process based on the model and compares the possible approaches for estimating both the runtime and capacity fade. Proposed methodology is verified on real measured data.
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